CN118564486A

CN118564486A - Pressure control method of air bearing assembly

Info

Publication number: CN118564486A
Application number: CN202410834940.4A
Authority: CN
Inventors: 邢纲
Original assignee: Zhejiang Oula Power Technology Co ltd
Current assignee: Zhejiang Oula Power Technology Co ltd
Priority date: 2024-06-26
Filing date: 2024-06-26
Publication date: 2024-08-30

Abstract

The utility model provides a pressure control method of air supporting bearing assembly, includes air supporting bearing assembly and the bearing air feed system who connects thereof, air supporting bearing assembly includes the main shaft, and thrust dish and axle sleeve have been cup jointed respectively to the main shaft periphery, are equipped with thrust piece between thrust dish and the bearing shell, and the axle sleeve periphery is equipped with the bearing shell, and the bearing shell periphery is equipped with the bearing frame, be equipped with the first air flue that provides radial load between axle sleeve and the main shaft, be equipped with the second air flue that provides axial load between thrust dish and the bearing shell side, the bearing shell side is equipped with the displacement sensor of response thrust dish position, bearing air feed system include air inlet line and the controller that provides air inlet pressure for first air flue. According to the pressure control method of the air bearing assembly, the controller is used for adjusting the air inlet pressure to control the air passage pressure of the first air passage and the second air passage according to the sensed displacement sensor data and the exhaust pressure of the first air passage.

Description

Pressure control method of air bearing assembly

Technical Field

The invention relates to the field of air bearing, in particular to an air bearing pressure control method for an air bearing used for a centrifugal compressor and provided with a bearing radial load and an axial load.

Background

The air bearing forms an air film between the air bearing and the main shaft through air, wherein the air enters a gap between the bearing and the rotor through micropores on the surface of the bearing, and forms air film pressure on a supporting part of the rotor, so that the air bearing plays a role in supporting the rotor to float.

At present, according to the lubrication mode of the air bearing, the air bearing is mainly divided into a static pressure air bearing and a dynamic pressure air bearing, compared with the dynamic pressure air bearing, the bearing capacity of the static pressure air bearing is 5-9 times of that of the dynamic pressure air bearing, the air bearing is mainly supplied to the bearing by means of an external high-pressure air source, the air enters a bearing gap through a restrictor by the air source, and then is continuously discharged from the outer edge of the bearing, so that an air film in the bearing gap obtains the bearing capacity (references J.W. POWELL, ding Weigang, lin Xiangqun and the like, and the air bearing is designed by the national defense industry publishing company).

According to patent CN210371677U, a three-way supported small hole throttling air bearing is disclosed, the bearing is composed of a radial bearing and thrust bearings arranged on two thrust surfaces, two thrust disks are arranged on a main shaft, and the composite bearing is arranged between the two thrust disks and bears radial and axial loads. The hydrostatic air bearing structures disclosed in the patent CN204003975U and the patent CN102494025A are similar in characteristics, two thrust surfaces and radial surfaces are processed on the main shaft, and the two thrust surfaces and the radial surfaces of the bearing are wrapped outside the main shaft and bear radial and axial loads. The air bearing structure disclosed in the three patents has the common point that a radial bearing surface and two thrust bearing surfaces are adopted to form a composite bearing, and the two thrust bearing surfaces are positioned on two sides of the radial bearing surface and are H-shaped, so that the air bearing structure is also called an H-shaped air bearing. As shown in patent CN113738661a, when the H-shaped air bearing is used in a centrifugal compressor shafting, the supporting end of the H-shaped air bearing must be matched with an independent radial air bearing at the same time, the H-shaped air bearing and the radial air bearing are respectively arranged at two sides of the motor rotor, one end bears radial and axial loads, and the other end bears radial loads.

According to the patent CN216343373U, a thrust air bearing assembly is disclosed, which is structured by arranging a single thrust disc on a main shaft, and arranging two thrust surfaces of the thrust air bearing on two sides of the thrust disc, wherein the two thrust surfaces are relatively thin and are relatively close to each other, and are combined with the thrust air bearing to form an I-type thrust bearing. As described in patent CN112628281a and patent CN106015032B, when the I-type thrust air bearing is used in a centrifugal compressor shafting, its support end must be matched with two independent radial air bearings at the same time, and the shafting supports two ends, one end is equipped with thrust bearing and radial bearing, and bears radial and axial load, and another end is equipped with radial bearing alone, and bears radial load.

The H-shaped bearing and the I-shaped bearing have two problems due to structural characteristics and shafting layout: the problem is that the structure of the bearing itself exists, the exhaust direction of the H-shaped bearing structure and the I-shaped bearing structure is the excircle side of the thrust gap, and the air film pressure distribution in the thrust gap has correlation with the exhaust direction of the air film, so that the pressure at the inner circle of the thrust bearing is obviously higher than the pressure at the excircle, the pressure gradient is larger, in addition, the thrust surface side of the H-shaped air bearing simultaneously takes account of the exhaust of the radial gap gas, the thrust gap and the radial gap gas form a seal, and the exhaust direction of the gas is 90 degrees, so that turbulence is easily formed in the inner circle of the thrust surface, the thermal deformation of the bearing body caused by friction heat generation is caused, and the laminar air film in the thrust gap is also easily damaged, so that the thrust surface is unbalanced, the thrust disc and the thrust surface are rubbed when the temperature rises instantly, the thrust sheet can fall off, and the bearing fails. The problem two is the problem that the structural layout of rotor brought, thrust bearing and radial bearing are arranged to main shaft one end, and radial bearing is arranged alone to the other end, and the bearing supports the load difference that both ends received great, to the rotor that the air supporting bearing supported, because gas viscosity is about 1/1000 of oil viscosity, the thickness of air film is very little, even receives external minute disturbance, causes the rotor unstability easily, leads to main shaft and bearing contact when serious, takes place to scrape or band-type axle, so the requirement is high to dynamic balance, and rotor structural layout's asymmetry is unfavorable for the execution of high accuracy dynamic balance technology.

In the rotor structure of the centrifugal compressor adopting the static pressure air bearing, the weight of the rotor is generally unchanged, the load born by the air bearing in the running process is very stable, and the damage to the bearing caused by radial load is less. Because the centrifugal compressor has abnormal working conditions such as instantaneous starting, instantaneous stopping, sudden acceleration, abrupt load change and the like in the running process, the axial load of the centrifugal compressor is greatly changed and is very unstable, impellers are respectively arranged at two ends of a rotor back to back in the shafting design process of the centrifugal compressor to offset most of axial thrust, but a small part of axial thrust is born by a thrust bearing, and when the centrifugal compressor has abnormal working conditions, the bearing capacity, rigidity and damping of the bearing are not timely adjusted according to the abnormal conditions, so that the axial vibration of the centrifugal compressor is increased, and even a thrust disc and the thrust bearing collide and scratch during severe conditions, and even the thrust disc is in thermal friction failure.

In patent CN203035757U, a combined type of single thrust bearing and radial bearing is also disclosed for a high-speed electric spindle air bearing assembly, the bearing appearance is similar to the air bearing of the present invention, 2O-rings are arranged on the outer circle of the radial bearing to provide additional damping, the vibration of the rotor cannot be completely eliminated under high-speed rotation, and the restrictor adopts a hole plate type, under the working condition of small clearance, the phenomenon of "air hammer" may be accompanied, when the clearance is reduced to a certain extent, the bearing rigidity is collapsed, and the rotor is extremely unstable to operate.

For the prior art, the object of the research of the person skilled in the art is an air bearing assembly method with stable air film formation and strong bearing capacity.

Disclosure of Invention

The invention aims at overcoming the defects and shortcomings of the prior art, and provides a pressure control method of an air bearing assembly, which enables a bearing to have a thrust gap automatic measurement function, and the thrust gap is controlled by actively adjusting air supply pressure, so that the running reliability of the air bearing assembly is further improved by reasonably designing an air passage and optimizing the integral structure of the bearing body.

In order to achieve the above purpose, the invention provides a pressure control method of an air bearing assembly, which comprises the air bearing assembly and a bearing air supply system connected with the air bearing assembly, wherein the air bearing assembly comprises a main shaft, the periphery of the main shaft is respectively sleeved with a thrust disc and a shaft sleeve, a bearing shell is arranged on the periphery of the shaft sleeve, a thrust piece is arranged between the thrust disc and the bearing shell, a bearing seat is arranged on the periphery of the bearing shell, a first air passage for providing radial load is arranged between the shaft sleeve and the main shaft, a second air passage for providing axial load is arranged between the thrust disc and the side surface of the bearing shell, a displacement sensor for sensing the position of the thrust disc is arranged on the side surface of the bearing shell, the first air passage and the second air passage are mutually communicated, the bearing air supply system comprises an air inlet pipeline for providing air inlet pressure for the first air passage, and a controller, and the controller is used for adjusting the air inlet pressure to control the air passage pressure of the first air passage and the second air passage according to sensed data of the displacement sensor. According to the pressure control method of the air bearing assembly, the gap between the thrust disc and the thrust piece is detected through the displacement sensor, the air pressure of the air inlet pipeline is correspondingly regulated, the pressure control of the first air passage and the second air passage of the air bearing assembly is realized, and unexpected abrasion caused by the gap change among the main shaft, the thrust disc and the shaft sleeve due to the pressure change of the first air passage and the second air passage is avoided.

The air inlet pipeline comprises a pressure pump, a storage tank, a regulating valve, a flowmeter and a second pressure sensor which are connected through pipelines, the regulating valve and the displacement sensor form linkage protection, the air inlet pressure of the first air passage and the second air passage is detected through the second pressure sensor, and the air inlet pressure is correspondingly regulated by the regulating valve so as to meet the air film thickness requirement in a gap; the storage tank is internally provided with a heater and a liquid level meter, the heater is used for controlling the pressure of the storage tank, the storage tank can store gas, liquid or gas-liquid two-phase fluid, the liquid level meter has a temperature measuring function, and meanwhile, the liquid level meter and the pressure pump form linkage protection and is used for controlling the liquid level and the fluid temperature in the storage tank; the storage tank is connected with a first pressure sensor for detecting the pressure of the storage tank, and the first pressure sensor and the heater form linkage protection.

The first air passage comprises an air inlet hole arranged on the bearing seat, the air inlet hole is communicated with a first groove arranged on the inner side of the bearing seat, the first groove is communicated with a radial air inlet hole and an axial air inlet hole in the bearing shell, the radial air inlet hole is communicated with an air groove air inlet of the shaft sleeve, a radial gap is formed between the shaft sleeve and the main shaft, the shaft sleeve is a porous ventilation medium, and air in the air groove air inlet is communicated with the radial gap. Under the action of gravity load, the spindle is eccentric relative to the shaft sleeve, the radial gap is not uniform around the outer circular surface gap of the spindle, an upper gap and a lower gap are formed, the upper gap and the lower gap are communicated with each other, the average value of the upper gap is larger than that of the lower gap, a gas film with a certain bearing capacity is formed in the gap and enveloped on the circumference of the spindle, and the floating operation of the spindle in the shaft sleeve is realized.

The shaft sleeve comprises a first annular surface and a second annular surface which are positioned at two ends, a transverse air groove and a longitudinal annular air groove which are communicated with an air groove air inlet are arranged between the first annular surface and the second annular surface, and the transverse air groove and the longitudinal annular air groove are uniformly distributed on the periphery of the shaft sleeve, so that air of the air groove air inlet can enter a radial gap through the shaft sleeve. The shaft sleeve is provided with a certain number of air grooves, so that air can be better distributed on the outer circular surface of the shaft sleeve, the air permeability of the porous air-permeable medium is very uniform, uniform air patterns can be formed in radial gaps, and stable air film pressure can be provided. The sleeve adopts the full porous medium as the restrictor, is also suitable for part of porous medium restrictors, and other restrictors such as small holes or micro holes, slit restrictors and the like are also suitable for other types of restrictors.

The bearing shell include the first radial annular face that is located the bearing shell medial surface, be located the second recess of bearing shell periphery, first radial annular face both sides all be equipped with radial glue storage groove, radial glue storage groove intercommunication injecting glue hole, through injecting glue hole to radial glue storage groove injection binder, the binder is full of and holds the glue groove, firmly bonds axle sleeve and bearing shell together.

The second air passage comprises an axial annular air groove positioned on the side surface of the bearing shell, the axial annular air groove is communicated with the axial air inlet hole, air in the axial annular air groove penetrates through the thrust piece and enters an axial gap between the thrust disc and the thrust piece, and the axial gap is communicated with the second air outlet hole of the bearing seat. The air film with certain bearing capacity is formed by the axial gap, and the effective thickness of the air film prevents the contact or abrasion between the thrust piece and the thrust disc, so that the service life of the air bearing assembly is prolonged.

The two sides of the axial annular air groove are respectively provided with a first annular glue storage groove and a second annular glue storage groove, a first radial air groove is communicated between the axial annular air groove and the first annular glue storage groove, and a second radial air groove is communicated between the axial annular air groove and the second annular glue storage groove. The first annular glue storage groove and the second annular glue storage groove are coated with the adhesive, the thrust piece and the bearing shell are firmly adhered together, the thrust piece is prevented from falling off under certain air inlet pressure, the first radial air groove and the second radial air groove are distributed in a scattering mode, uniform permeation of air through the thrust piece is facilitated, a uniform air film of pressure distribution is formed in an axial gap, and sufficient axial bearing capacity is ensured to be provided.

The thrust piece and the shaft sleeve are made of porous medium materials, the application of the material in the static pressure air bearing is wider and wider, the porous medium materials are applied to the air bearing, and the main advantages of the porous medium materials are that the air film surface pressure is uniformly distributed, the pressure drop phenomenon does not exist, the air hammer phenomenon is not easy to be caused, the operation is more stable under the action of larger overturning moment, the porous medium materials are suitable for single-component gas and multicomponent mixed gas, and the porous medium materials have stronger adaptability to different states of fluid such as gas state, liquid state and gas-liquid two-phase state. The porous medium material has relatively perfect development at present, has ready-to-use mature and available raw materials, and can be rapidly engineered.

The main shaft, the thrust disc, the shaft sleeve and the bearing shell mutually surround to form a first cavity, the sealing end cover is arranged on the periphery of the thrust disc, the sealing end cover, the bearing shell and the bearing seat mutually surround to form a second cavity, and the first cavity and the second cavity are communicated with a first exhaust hole in the bearing shell through an axial gap, namely, the first air passage and the second air passage are mutually communicated, so that the air floatation bearing assembly is ensured to have stable intercommunicating air inlet and exhaust passages. The arrangement of the first exhaust hole is beneficial to timely discharging gas in the axial gap and the radial gap, and heat generated by gas friction in the gap can be timely taken away, so that the working temperature of a gas film in the gap is reduced, a series of problems caused by thermal stress or thermal expansion are eliminated, and particularly, the thrust piece is beneficial to improving overturning rigidity, the bearing capacity is more stable, and the risk brought by the abnormal working condition of the compressor can be effectively reduced.

And a sealing gap is arranged between the sealing end cover and the thrust plate.

By adopting the technical scheme, the pressure control method of the air bearing assembly detects the gap between the thrust disc and the thrust piece through the displacement sensor, and correspondingly adjusts the air pressure of the air inlet pipeline, so that the pressure control of the first air passage and the second air passage of the air bearing assembly is realized, and the running stability of the air bearing assembly is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a method of controlling pressure in an air bearing assembly according to the present invention;

FIG. 2 is a schematic structural view of an air bearing assembly according to the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is a schematic perspective cross-sectional view of a bearing housing according to the present invention;

FIG. 5 is a schematic perspective view of a shaft sleeve according to the present invention;

FIG. 6 is a schematic view of the thrust piece and bushing mounting structure of the present invention;

FIG. 7 is a schematic illustration of a symmetrical rotor air bearing arrangement in accordance with the present invention;

FIG. 8 is a schematic diagram of the radial bearing of the bushing of the present invention;

FIG. 9 is a cross-sectional view B-B of FIG. 8;

Fig. 10 is a schematic axial bearing diagram of a thrust piece in the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.

As shown in fig. 1-10, a pressure control method of an air bearing assembly comprises the air bearing assembly and a bearing air supply system connected with the air bearing assembly, the air bearing assembly comprises a main shaft 1, an anti-thrust disc 9 and a shaft sleeve 2 are respectively sleeved on the periphery of the main shaft 1, a bearing shell 3 is arranged on the periphery of the shaft sleeve 2, a thrust piece 7 is arranged between the anti-thrust disc 9 and the bearing shell 3, a bearing seat 5 is arranged on the periphery of the bearing shell 3, a first air passage for providing radial load is arranged between the shaft sleeve 2 and the main shaft 1, a second air passage for providing axial load is arranged between the anti-thrust disc and a bearing shell side 3p, a displacement sensor 6 for sensing the position of the anti-thrust disc is arranged on the bearing shell side 3p, the displacement sensor 6 is arranged in a mounting hole 3k of the bearing shell side 3p, the first air passage and the second air passage are mutually communicated, the bearing air supply system comprises an air inlet pipeline for providing air inlet pressure Po for the first air passage, and a controller 13, and the controller 13 is used for controlling the pressure of the first air passage and the second air passage according to sensed displacement sensor data combined with the air outlet pressure Pa of the first air passage. The thrust piece 7 and the shaft sleeve 2 are vertically arranged to be T-shaped and respectively bear axial load and radial load. The T-shaped air bearing is used in pairs, the two bearings have the same size and specification, interchangeability can be realized, and the main shaft characteristics require symmetrical arrangement. The two sides of the main shaft 1 are provided with a bearing shell 3, a thrust disc 9 and an impeller 54. The thrust piece 7 is annular, the shaft sleeve 2 is cylindrical, and both the thrust piece and the shaft sleeve have certain thickness. The bearing shell 3 comprises a first radial annular surface 3r positioned on the inner side surface of the bearing shell 3 and a second groove 3a positioned on the outer periphery of the bearing shell 3, the second groove 3a is matched with and provided with a first O-shaped ring 4, both sides of the first radial annular surface 3r are respectively provided with a radial glue storage groove 3O, and the radial glue storage grooves 3O are communicated with a glue injection hole 3n.

The air inlet pipeline comprises a pressure pump 14, a storage tank 15, a regulating valve 17, a flowmeter 18 and a second pressure sensor 19 which are connected through pipelines; a heater 20 and a liquid level meter 21 are arranged in the storage tank 15, and a first pressure sensor 16 is connected to the outside of the storage tank 15.

The first air passage comprises an air inlet hole 5b arranged on the bearing seat 5, the air inlet hole 5b is communicated with a first groove 5a arranged on the inner side of the bearing seat 5, the first groove 5a is communicated with a radial air inlet hole 3b and an axial air inlet hole 3c in the bearing shell 3, the radial air inlet hole 3b is communicated with an air groove air inlet 2c of the shaft sleeve 2, a radial gap q2 is formed between the shaft sleeve 2 and the main shaft 1, the shaft sleeve 2 is a porous ventilation medium, and air in the air groove air inlet 2c is communicated with the radial gap q2. The side of the bearing seat 5 is provided with a second groove 5d, the second groove 5d is annular and is axially provided with a second O-shaped ring 12, and the exhaust notch of the first groove 5a is chamfered to form an inclined surface 5e, so that the communication performance of the first groove 5a and the radial air inlet hole 3b is improved. Since the spindle 1 is eccentric with respect to the sleeve 2 by the gravity load (G), the radial gap (q 2) is not uniform around the outer circumferential surface of the spindle 1, forming an upper gap (q 2 a) and a lower gap (q 2 b) which are communicated with each other and the average value of the upper gap (q 2 a) is larger than that of the lower gap (q 2 b). The inclined surface 5e has the main function of facilitating the first O-shaped ring to smoothly pass through the first groove in the assembly process of the bearing shell, and simultaneously preventing the first O-shaped ring from being scratched during the assembly process. The shaft sleeve 2 comprises a first annular surface 2a and a second annular surface 2e which are positioned at two ends, and a transverse air groove 2b and a longitudinal annular air groove 2d which are communicated with an air groove air inlet 2c are arranged between the first annular surface 2a and the second annular surface 2 e. The thrust disc 9 is sleeved on the main shaft 1 and is arranged on the outer side of the thrust piece 7 to form an axial gap q1, and the bearing must ensure the minimum gap range of the axial gap q1 and the radial gap q2 in the working process, so that the shaft sleeve 2 is prevented from contacting the main shaft 1, and the thrust piece 7 is prevented from contacting the thrust disc 9.

The second air passage comprises an axial annular air groove 3d positioned on the side surface 3p of the bearing shell, the axial annular air groove 3d is communicated with an axial air inlet hole 3c, air in the axial annular air groove 3d penetrates through the thrust piece 7 and enters an axial gap q1 between the thrust disc 9 and the thrust piece 7, and the axial gap q1 is communicated with a second air outlet hole 5c of the bearing seat 5.

The two sides of the axial annular air groove 3d are respectively provided with a first annular glue storage groove 3i and a second annular glue storage groove 3j, a first radial air groove 3e is communicated between the axial annular air groove 3d and the first annular glue storage groove 3i, a second radial air groove 3f is communicated between the axial annular air groove 3d and the second annular glue storage groove 3j, the second radial air grooves 3f and the first radial air grooves 3e are in radial scattering cross arrangement for a certain number, so that uniform permeation of gas through the thrust piece 7 is facilitated, a gas film with uniform pressure distribution is formed in the axial gap q1, and sufficient axial bearing capacity is ensured. The thrust piece 7 is arranged on the outer side surfaces of the first radial air groove 3e and the second radial air groove 3f, and a sufficient amount of adhesive is smeared in the plurality of first annular adhesive storage grooves 3i and the second annular adhesive storage grooves 3j which are V-shaped to bond the thrust piece 7 and the bearing shell 3 together, and the side surface 3p of the bearing shell is ensured to be slightly lower than the thrust piece 7.

The main shaft 1, the thrust disc 9, the shaft sleeve 2 and the bearing housing 3 are preferably mutually surrounded to form a first cavity 10, the sealing end cover 8 is arranged on the periphery of the thrust disc 9, the sealing end cover 8, the bearing housing 3 and the bearing seat 5 are mutually surrounded to form a second cavity 11, and the first cavity 10 and the second cavity 11 are communicated through an axial gap q1 and a first exhaust hole 3g in the bearing housing 3. The first exhaust holes 3g are arranged in a radial scattering shape along the bearing housing 3 by a certain amount. A sealing gap q3 is arranged between the sealing end cover 8 and the thrust disk 9.

The invention relates to a pressure control method of an air bearing assembly, which comprises the following steps: the gas of the bearing gas supply system enters the bearing shell through the gas inlet hole 5b and the first groove 5a, wherein the gas of the first gas channel sequentially enters the transverse gas groove 2b and the longitudinal annular gas groove 2d of the shaft sleeve 2 through the radial gas inlet hole 3b, the gas is discharged through the radial gap q2 after penetrating and throttling through the shaft sleeve 2, the gas of the second gas channel sequentially enters the axial annular gas groove 3d through the axial gas inlet hole 3c, and is discharged through the axial gap q1 after penetrating and throttling through the first radial gas groove 3e and the second radial gas groove 3f through the thrust piece 7, one part of the gas discharged through the axial gap q1 enters the first cavity 10, the other part of the gas is divided into two paths, one path of the gas is discharged through the sealing gap q3, and the other path of the gas directly enters the second cavity 11 to be mixed with the gas of the first gas outlet hole 3g and then is discharged through the second gas outlet hole 5 c. The first gas is discharged along both sides of the sleeve 2 through the radial gap q2, wherein one side is directly discharged through the first chamber 10, the first exhaust hole 3g, the second chamber 11 and the second exhaust hole 5 c.

As a control method of the controller 13, the intake pressure Po generates osmotic pressure at the radial gap q2 and the axial gap q1 through the boss 2 and the thrust piece 7, wherein the osmotic pressure Ps at the upper gap q2a, the osmotic pressure Pn at the lower gap q2b, the osmotic pressure Pz at the average radius of the axial gap q1, the pressures Ps, pn, and Pz are regulated by the differential pressure of the intake pressure Po and the exhaust pressure Pa.

The gap and the flow of the air bearing are in a cubic relation, the larger the gap is, the larger the exhaust flow is, the smaller the exhaust resistance is, the pressure Ps < Pn is caused by the fact that the gap q2a is larger than q2b, the bearing capacity L x D x (Ps-Pa) < L x D x (Pn-Pa) of the upper and lower parts of the main shaft 1 is correspondingly acted, the main shaft 1 is floated under the action of the difference of the upper bearing capacity and the lower bearing capacity, the larger the air inlet pressure Po is, the larger the pressure Ps and Pn is, the smaller the difference of the upper bearing capacity and the lower bearing capacity of the main shaft 1 is, the bearing capacity of the shaft sleeve 2 is higher, the center line of the main shaft 1 is close to the center line of the shaft sleeve 2, and the radial gap q2 is ensured to be larger than a certain minimum value for safety. L is the length of the shaft sleeve 2, D is the diameter of the main shaft 1, and a corresponding functional relation is established between the radial load and the radial gap q2 through a test.

The bearing capacity acting on the thrust piece 7 is pi× (Pz-Pa) × (Ro ²-Ri²), the greater the intake pressure Po, the greater the pressure Pz, and the greater the corresponding bearing capacity, the greater the axial thrust load variation of the centrifugal compressor, so that it is necessary to ensure the minimum safety distance of the axial gap q1, the axial gap q1 being detected by a certain number of displacement sensors 6, and the intake pressure Po being regulated according to the detected value. Ro is the outer diameter of the thrust piece 7, ri is the inner diameter of the thrust piece 7, and a corresponding functional relation is established between the axial load and the axial gap q1 through a test.

The controller 13 receives signals of the displacement sensor 6, the intake pressure Po, the exhaust pressure Pa, and the pressure Pc of the tank 15, respectively. The controller 13, after receiving the signal of the motion sensor 6, judges whether the motion sensor is in a reasonable range, if the axial gap q1 is too small, the controller 13 sends out an adjusting instruction to control the opening degree of the adjusting valve 17 to increase the value of Po, and the larger the air inlet and exhaust pressure difference Po-Pa is, the larger the axial gap q1 is, the closer the values of the upper gap q2a and the lower gap q2b of the radial gap q2 are, and the stronger the bearing capacity of the air bearing is, otherwise, since the air bearing is. The larger the intake and exhaust pressure difference Po-Pa is not, the better the bearing capacity is, but the rigidity of the bearing is weakened correspondingly, the capability of resisting external disturbance is weakened, so the controller 13 can control the intake and exhaust pressure difference Po-Pa to fluctuate within a certain range according to the actual running condition of the bearing.

The first pressure sensor 16 detects the pressure in the tank 15 and if the pressure Pc is too low, the controller 13 is required to instruct to start the heater 20 to heat the gas to increase its pressure in order to ensure Pc > Po. The liquid level meter 21 is used for detecting the liquid level of the liquid in the storage tank 15, if the liquid level is too low, the controller 13 sends out a command to start the pressure pump 14 for supplying liquid until reaching a certain liquid level, and in addition, the liquid level meter has a temperature measuring function, so that the temperature of the liquid in the storage tank can be timely reflected.

Because the thrust piece and the shaft sleeve share one set of air supply system, when the axial air gap q1 is adjusted, the air supply pressure difference (Po-Pa) of the thrust piece and the shaft sleeve is the same, and because the bearing capacity of the shaft sleeve fully considers the change condition of the axial load at the beginning of the design selection, when the axial load is adjusted, the bearing capacity of the shaft sleeve supports the radial load of the whole rotor relative to the axial load, and enough allowance is reserved.

The invention adopts a shaft sleeve and a thrust piece to form an air bearing assembly which bears radial load and axial load, and the thrust piece is vertical to the central line of the shaft sleeve and is in a T shape. The structural form of the T-shaped air bearing is more favorable for adopting symmetrical shafting layout, two supporting points of the rotor can be respectively provided with the air bearing with the same specification and size, the load born by each air bearing is close, the two air bearing can be interchanged, the arrangement production is favorable, and the manufacturing cost of the air bearing is reduced.

While embodiments of the present invention have been shown and described, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations may be made in the above embodiments by those skilled in the art without departing from the spirit and principles of the invention. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The pressure control method of the air bearing assembly comprises the air bearing assembly and a bearing air supply system connected with the air bearing assembly, and is characterized in that: the air bearing assembly comprises a main shaft (1), a thrust disc (9) and a shaft sleeve (2) are sleeved on the periphery of the main shaft (1) respectively, a bearing shell (3) is arranged on the periphery of the shaft sleeve (2), a thrust piece (7) is arranged between the thrust disc (9) and the bearing shell (3), a bearing seat (5) is arranged on the periphery of the bearing shell (3), a first air passage for providing radial load is arranged between the shaft sleeve (2) and the main shaft (1), a second air passage for providing axial load is arranged between the thrust disc and a side face (3 p) of the bearing shell, a displacement sensor (6) for sensing the position of the thrust disc is arranged on the side face (3 p) of the bearing shell, the first air passage and the second air passage are mutually communicated, the bearing air supply system comprises an air inlet pipeline for providing air inlet pressure (Po) for the first air passage, and a controller (13), and the pressure of the first air passage and the second air passage are controlled according to sensed by the displacement sensor data in combination with the exhaust pressure (Pa) of the first air passage.

2. The method of pressure control of an air bearing assembly according to claim 1, wherein: the air inlet pipeline comprises a pressure pump (14), a storage tank (15), a regulating valve (17), a flowmeter (18) and a second pressure sensor (19) which are connected through pipelines; a heater (20) and a liquid level meter (21) are arranged in the storage tank (15), and a first pressure sensor (16) is connected to the outside of the storage tank (15).

3. The method of pressure control of an air bearing assembly according to claim 1, wherein: the first air passage comprises an air inlet hole (5 b) formed in the bearing seat (5), the air inlet hole (5 b) is communicated with a first groove (5 a) formed in the inner side of the bearing seat (5), the first groove (5 a) is communicated with a radial air inlet hole (3 b) and an axial air inlet hole (3 c) in the bearing shell (3), the radial air inlet hole (3 b) is communicated with an air groove air inlet (2 c) of the shaft sleeve (2), a radial gap (q 2) is formed between the shaft sleeve (2) and the main shaft (1), the shaft sleeve (2) is a porous ventilation medium, and air in the air groove air inlet (2 c) is communicated with the radial gap (q 2).

4. A method of controlling the pressure of an air bearing assembly according to claims 1 and 3, wherein: the main shaft (1) is eccentric relative to the shaft sleeve (2) under the action of gravity load (G), the radial gap (q 2) is not uniform around the outer circular surface of the main shaft (1), an upper gap (q 2 a) and a lower gap (q 2 b) are formed, and the average value of the upper gap (q 2 a) is larger than that of the lower gap (q 2 b).

5. A method of controlling the pressure of an air bearing assembly according to claim 3, wherein: the shaft sleeve (2) comprises a first annular surface (2 a) and a second annular surface (2 e) which are positioned at two ends, and a transverse air groove (2 b) and a longitudinal annular air groove (2 d) which are communicated with an air groove air inlet (2 c) are arranged between the first annular surface (2 a) and the second annular surface (2 e).

6. The method of pressure control of an air bearing assembly according to claim 1, wherein: the bearing shell (3) comprises a first radial annular surface (3 r) positioned on the inner side surface of the bearing shell (3), and a second groove (3 a) positioned on the periphery of the bearing shell (3), wherein radial glue storage grooves (3 o) are formed in two sides of the first radial annular surface (3 r), and the radial glue storage grooves (3 o) are communicated with glue injection holes (3 n).

7. The method of pressure control of an air bearing assembly according to claim 1, wherein: the second air passage comprises an axial annular air groove (3 d) positioned on the side surface (3 p) of the bearing shell, the axial annular air groove (3 d) is communicated with an axial air inlet hole (3 c), air in the axial annular air groove (3 d) permeates through the thrust piece (7) and enters an axial gap (q 1) between the thrust disc (9) and the thrust piece (7), and the axial gap (q 1) is communicated with a second air outlet hole (5 c) of the bearing seat (5).

8. The method of pressure control of an air bearing assembly according to claim 7, wherein: the two sides of the axial annular air groove (3 d) are respectively provided with a first annular glue storage groove (3 i) and a second annular glue storage groove (3 j), a first radial air groove (3 e) is communicated between the axial annular air groove (3 d) and the first annular glue storage groove (3 i), and a second radial air groove (3 f) is communicated between the axial annular air groove (3 d) and the second annular glue storage groove (3 j).

9. The method of pressure control of an air bearing assembly according to claim 1, wherein: the novel anti-thrust bearing comprises a main shaft (1), an anti-thrust disc (9), a shaft sleeve (2) and a bearing shell (3), wherein a first cavity (10) is formed by surrounding each other, a sealing end cover (8) is arranged on the periphery of the anti-thrust disc (9), a second cavity (11) is formed by surrounding each other by the sealing end cover (8), the bearing shell (3) and a bearing seat (5), and the first cavity (10) and the second cavity (11) are communicated through an axial gap (q 1) and a first exhaust hole (3 g) in the bearing shell (3), and a sealing gap (q 3) is formed between the sealing end cover (8) and the anti-thrust disc (9).

10. The method of pressure control of an air bearing assembly according to claim 1, wherein: the gas of the bearing gas supply system enters the bearing shell through the gas inlet hole (5 b) and the first groove (5 a), wherein the gas of the first gas channel sequentially enters the transverse gas groove (2 b) and the longitudinal annular gas groove (2 d) of the shaft sleeve 2 through the radial gas inlet hole (3 b), the gas is discharged through the radial gap (q 2) after being permeated and throttled through the shaft sleeve (2), the gas of the second gas channel sequentially enters the axial annular gas groove (3 d) through the axial gas inlet hole (3 c), the gas is discharged through the axial gap (q 1) after being permeated and throttled through the first radial gas groove (3 e) and the second radial gas groove (3 f) through the thrust piece 7, one part of the discharged gas of the axial gap (q 1) enters the first cavity (10), the other part of the discharged gas is divided into two paths, one path of the gas is discharged through the sealing gap (q 3), the other path of the gas directly enters the second cavity (11) and is discharged through the second gas outlet hole (5 c) after being mixed with the gas of the first outlet hole (3 g), and the gas of the first gas channel is discharged through the radial gap (q 2) along two sides of the shaft sleeve (2), wherein one side of the gas is discharged through the first cavity (10), the first gas outlet hole (3 g) and the second gas outlet hole (5 g) are directly discharged.