KR101803058B1 - thrust control apparatus for air foil bearing of turbo compressor - Google Patents

thrust control apparatus for air foil bearing of turbo compressor Download PDF

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Publication number
KR101803058B1
KR101803058B1 KR1020150130553A KR20150130553A KR101803058B1 KR 101803058 B1 KR101803058 B1 KR 101803058B1 KR 1020150130553 A KR1020150130553 A KR 1020150130553A KR 20150130553 A KR20150130553 A KR 20150130553A KR 101803058 B1 KR101803058 B1 KR 101803058B1
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KR
South Korea
Prior art keywords
airfoil
thrust
bearing
shaft
rotating disk
Prior art date
Application number
KR1020150130553A
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Korean (ko)
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KR20170032757A (en
Inventor
정완용
장인배
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정완용
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Priority to KR1020150130553A priority Critical patent/KR101803058B1/en
Publication of KR20170032757A publication Critical patent/KR20170032757A/en
Application granted granted Critical
Publication of KR101803058B1 publication Critical patent/KR101803058B1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/04—Shafts or bearings, or assemblies thereof
    • F04D29/041—Axial thrust balancing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/04—Shafts or bearings, or assemblies thereof
    • F04D29/046—Bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/04—Shafts or bearings, or assemblies thereof
    • F04D29/046—Bearings
    • F04D29/048—Bearings magnetic; electromagnetic
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C17/00—Sliding-contact bearings for exclusively rotary movement
    • F16C17/04—Sliding-contact bearings for exclusively rotary movement for axial load only
    • F16C17/042—Sliding-contact bearings for exclusively rotary movement for axial load only with flexible leaves to create hydrodynamic wedge, e.g. axial foil bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C39/00—Relieving load on bearings
    • F16C39/06—Relieving load on bearings using magnetic means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/12—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring axial thrust in a rotary shaft, e.g. of propulsion plants
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2360/00—Engines or pumps
    • F16C2360/44—Centrifugal pumps

Abstract

The present invention discloses an airfoil bearing thrust control apparatus for a turbo compressor capable of drastically improving durability and operational reliability of an airfoil bearing by measuring a bearing load using a load cell and canceling it with a magnetic force of an electromagnet.
The present invention relates to an air conditioner comprising an impeller, a shaft connected to the rear of the impeller so that the impeller can rotate, a hollow housing surrounding the shaft, a motor mounted inside the housing to rotate the shaft, A plurality of airfoil journal bearings for supporting a rotating shaft, an airfoil thrust bearing for supporting a rotating disk formed on one side of the shaft, and a plurality of airfoil thrust bearings for supporting the rotating disk, A measuring device installed inside the first space for measuring an axial load applied to the rotating disk; a measuring device installed in the first space so as to face the rotating disk, An airfoil bearing thrust for a turbo compressor comprising a pushing and pulling means It relates to an apparatus.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a thrust control apparatus for an airfoil bearing,

The present invention relates to an airfoil bearing thruster for a turbocompressor, and more particularly, to a method of controlling an airfoil bearing thruster of a turbocompressor by measuring the bearing load using a load cell and canceling the load by using the magnetic force of the electromagnet, thereby dramatically improving the durability and reliability of the airfoil bearing. To an airfoil bearing thrust force adjusting device for a turbo compressor.

The airfoil bearing, which is conventionally referred to as a garret bearing, is formed by rolling the foils (1, 3) of a thin plate in a half-moon shape and superimposing them on each other as shown in FIGS. 1 and 2, This is an air dynamic pressure bearing which is used for the high-speed spindle because of its low frictional force in the high-speed rotation state.

However, air foil bearings generate air dynamic pressure which can only serve as bearings in an ultra-high speed rotation state, and when the rotation shaft stops, there is a disadvantage that the bearing foil wears due to insufficient dynamic pressure. Therefore, durability and reliability are not secured, It was not applied to industrial bearings.

However, with the development of diamond (high strength carbon) coating technology on sheet metal surfaces in the 1990s, attempts have been made to apply airfoil bearings to turbochargers and turbo blowers.

Particularly, in the case of a turbo blower using a centrifugal pump system including an impeller 4, a shaft 5, a housing 6 and a motor 7 as shown in Fig. 3, a built-in motor system is adopted, Excellent blowing models have also been developed, resulting in very large commercial success.

However, in the case of the centrifugal pump type turbo blower, thrust in the axial direction is generated in the air compression process. The thrust is supposed to be supported by the disc-shaped thrust bearing 8 as shown in FIG. 4, The centrifugal blower having durability and reliability is commercialized because the disk-shaped airfoil bearing can sufficiently support the load due to the thrust.

Recently, attempts have been made to apply the centrifugal pumps using airfoil bearings to air compressors that generate 7 to 9 atmospheres using two or three stages. First, in the case of the two-stage compressor, when the air introduced into the low-pressure stage is radially discharged, the air whose temperature has risen by the adiabatic compression is passed through the heat exchanger and cooled. The compressed air is radially discharged. In the case of the two-stage centrifugal compressor, as shown in Fig. 5, impeller thrusts are generated in opposite directions to each other at the impellers 9 and 9 'installed so as to be opposite to each other, Since the diameter of the impeller for compression is larger than that of the high-pressure stage impeller, the thrust in the direction of the low-pressure inlet remains. Such axial thrust can be reduced to some extent through the design of the impeller and the load distribution, but it is designed only for specific speed and flow ratio, and the thrust fluctuation occurs in the flow rate control or the speed control process for the capacity control.

In particular, as shown in Fig. 6, in the case of a compressor for compressing 7 to 9 atmospheres, there is no problem because the load added to the thrust bearing for supporting the self weight of the shaft is not much different from that of the blower, Since the compression ratio is as high as 10 times as much as that of the blower, a much larger thrust is generated than the blower. This causes a severe bearing wear as shown in FIG. 7 because the thrust bearing approaches a critical load to be applied. Commercialization of a centrifugal turbo air compressor has been delayed.

In order to overcome this problem, centrifugal blowers and centrifugal compressors using magnetic levitation type magnetic bearings have recently been introduced. However, since the reliability of the centrifugal blowers and the centrifugal compressors have not yet been proved and magnetic bearings are very expensive, to be.

Korean Patent Publication No. 10-2009-0062075

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the problems described above, and it is an object of the present invention to provide an airfoil bearing which measures a bearing load using a load cell and cancels the load by a magnetic force of an electromagnet to drastically improve durability and operation reliability And an airfoil bearing thrust force adjusting device for the turbo compressor.

In order to achieve the above object, according to one aspect of the present invention, there is provided an air conditioner comprising: an impeller; a shaft connected to the rear of the impeller to allow the impeller to rotate; a hollow housing surrounding the shaft; A plurality of airfoil journal bearings for supporting a shaft rotatably supported on the shaft, an airfoil thrust bearing for supporting a rotating disk formed on one side of the shaft, Measuring means for measuring an axial load exerted on the rotary disk, the measuring means being installed at one side of the housing to receive the rotary disk and inside a first space formed in communication with the hollow, And the rotating disk is moved toward one side in accordance with the measurement result of the measuring means The present invention provides an airfoil bearing thrust regulating device for a turbo compressor, comprising an adjusting means for pushing or pulling.

The control unit may further include a calculation unit that receives the measurement result of the measurement unit and compares the measured reference load with a predetermined reference thrust and outputs the comparison result, and a conversion unit that receives the comparison result of the calculation unit and converts the control gain into a control gain of the adjustment unit do.

Further, the measuring means is provided as a load cell or a displacement sensor.

In addition, the adjusting means is provided as a hybrid magnet in which an electromagnet or an electromagnet and a permanent magnet are mixed.

According to the present invention, the bearing load is measured by using the load cell, and the bearing load is canceled by the magnetic force of the electromagnet, thereby remarkably improving the durability and operational reliability of the airfoil bearing.

In addition, by incorporating means capable of canceling the thrust against the biased thrust, it is possible to complement the support force of the airfoil thrust bearing and also to prevent the airfoil thrust bearing from being damaged.

In addition, it is possible to selectively apply physical force to the airfoil thrust bearing selectively only when necessary, thereby preventing unnecessary power consumption and minimizing wear of the airfoil thrust bearing.

FIGS. 1 and 2 are sectional views showing a state in which a conventional airfoil journal bearing is fitted in a shaft,
3 is a cross-sectional view of a conventional turbo blower equipped with an airfoil bearing,
4 is a plan view of a conventional airfoil thrust bearing,
5 is a cross-sectional view of a two-stage centrifugal compressor equipped with a conventional airfoil bearing,
FIG. 6 is a graph showing a change in thrust force of a conventional centrifugal compressor,
7 is a photograph showing a state where a conventional airfoil thrust bearing is damaged,
8 is a cross-sectional view of a turbo compressor equipped with an airfoil bearing thruster according to an embodiment of the present invention,
9 is a control flow chart of the adjustment means for thrust cancellation.

The airfoil bearing thrust force adjusting device for a turbo compressor according to the present invention can measure the bearing load using a load cell and offset it by the magnetic force of the electromagnet to drastically improve the durability and operational reliability of the airfoil bearing. An embodiment is shown in Figs. 8 to 9. Fig.

FIG. 8 is a cross-sectional view of a turbo compressor equipped with an airfoil bearing thrust control apparatus according to an embodiment of the present invention, and FIG. 9 is a control flowchart of a throttle canceling control means.

The airfoil bearing thruster of the present invention includes measuring means (210) and conditioning means (220).

An airfoil bearing thrust control apparatus according to the present invention includes an impeller 110, a shaft 120 connected to the rear of the impeller 110 to allow the impeller 110 to rotate, A hollow housing 140, a motor 150 mounted inside the housing 140 to rotate the shaft 120, and a plurality of rotatable shafts 130 And an air foil thrust bearing 170 for supporting a rotary disk 131 formed on one side of the shaft 130. The air foil bearing thrust force adjusting device of the turbo compressor of the present invention includes:

The measuring unit 210 is installed on the inner side of the first space 141 formed to communicate with the hollow space on one side or the other side of the housing 140 to receive the rotating disk 131, Is measured.

The adjusting means 220 may be installed inside the housing 140 so as to face the rotating disc 131 accommodated in the first space 141. The adjusting means 220 may be installed in the housing 140, (131) is pushed or pulled to one side. At this time, the adjusting means 220 is in the form of a supporting plate of the airfoil thrust bearing 170, and an airfoil thrust bearing 170 may be disposed between the adjusting means 220 and the rotating disk 131. The adjusting means 220 may be formed on one side or the other side of the rotating disk 131, or on both sides of the rotating disk 131.

For example, when forward biased thrust is generated as shown in FIG. 8, a pushing force is applied to the rotating disk 131 and the shaft 120 to push backward, and thrust must be canceled.

On the other hand, when the backwardly biased thrust is generated, the pushing force is applied to the rotating disk 131 and the shaft 120 forward to cancel the thrust.

According to the present invention, a physical force is applied to the rotating disk 131 through the adjusting means 220 so that the thrust due to the axial acting force difference generated in the compression process of the compressor does not apply an excessive thrust to the airfoil thrust bearing 170 The damage to the airfoil thrust bearing 170 can be reduced and commercial durability and reliability can be ensured.

In addition, the thrust regulator according to the present invention operates the regulating means 220 only when the compressor generates the compression force, thereby canceling the thrust, and the force for canceling the thrust can be varied during the discharge capacity control or the no-load operation.

Therefore, after the axial thrust is measured through the measuring means 210, only when necessary, the adjusting means 220 is subjected to feedback control so that the adjusting means 220 can cancel the axial thrust.

According to an embodiment of the present invention, the measuring unit 210 may be a load cell or a displacement sensor.

In addition, according to another embodiment of the present invention, the adjusting means 220 may be provided as an electromagnet or a hybrid magnet in which an electromagnet and a permanent magnet are mixed.

8, the axial thrust is directed toward the low-pressure end having a large diameter of the impeller, and an electromagnetic force is applied to the rotary disk 131 formed on one side of the shaft 120 in order to cancel it.

At this time, it is preferable that the rotating disk 131 is formed of a metal material of a magnetic substance which can be influenced by the magnetic force of the electromagnet or the hybrid magnet. The magnitude of the electromagnetic force generated in the electromagnet or hybrid magnet corresponds to the axial load measured by the measuring means 210 such as a load cell supporting the airfoil thrust bearing 170 and feedbacks the measured axial load Should be offset. Thus, the excessive thrust applied to the airfoil thrust bearing 170 is reduced, so that the life and reliability of the airfoil thrust bearing 170 are greatly improved.

In this case, the ring-shaped electromagnet should be designed to be able to serve as a backplate of the airfoil thrust bearing 170, but this can easily be realized by a ceramic-steel joint structure or the like.

In addition, the thrust measured by the measuring means 210 such as a load cell is fed back through a low-pass filter so that the adjusting means 220 such as an electromagnet suddenly changes the acting force to cause unintentional damage to the airfoil thrust bearing 170 You can prevent it from being applied.

9 is a control flow chart of the adjustment means for thrust cancellation.

According to another embodiment of the present invention, there is provided an apparatus for measuring a load, comprising: an arithmetic unit for receiving a measurement result of the measurement unit 210 to compare a predetermined reference thrust with a measured load; And a conversion unit for converting the signal into a gain and outputting the signal.

The reference thrust is a preload of the airfoil thrust bearing 170, which means a load applied to the measurement means 210 when no load is applied, and may be set to zero or a specific value.

The thrust applied to the shaft 120 while the compressor compresses the air can be measured (S110) by the measuring means 210 installed at the base of the airfoil thrust bearing 170 located outside, The feedback can be made after the noise is removed. Thereafter, the measurement thrust of the measuring means 210 is compared with the reference thrust (S120), and the error is input to a calculation means such as a PID controller through the calculation unit 210. Based on the calculated error, the control gain is calculated (S130) The current output (S140) is then made for control of the regulating means (220).

For example, when the adjusting means 220 is made of an electromagnet, the rotating disk 131 and the shaft 120 can be pulled or pushed in proportion to the supplied current, thereby canceling thrust due to air compression The load applied to the airfoil thrust bearing 170 can be reduced, and the reliability and life of the airfoil thrust bearing 170 can be remarkably increased.

According to the present invention as described above, the bearing load is measured using a measuring means such as a load cell, and the durability and operational reliability of the airfoil bearing are significantly improved by offsetting the bearing load by the magnetic force or the physical force of the adjusting means such as an electromagnet There are advantages to be able to.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention.

Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

110: impeller 120: shaft
131: rotating disk 140: housing
141: first space 150: motor
160: Airfoil journal bearings
170: airfoil thrust bearing
210: measuring means 220: adjusting means

Claims (4)

A shaft connected to the rear of the impeller to allow the impeller to rotate; a hollow housing surrounding the shaft; a motor mounted inside the housing to rotate the shaft; An airfoil bearing thrust control apparatus for a turbo compressor, comprising: a plurality of airfoil journal bearings for supporting a shaft; and an airfoil thrust bearing for supporting a rotating disk formed on one side of the shaft,
Measuring means for measuring an axial load applied to the rotating disk, the measuring means being installed at one side of the housing to receive the rotating disk, the measuring means being installed in a first space communicating with the hollow;
Adjusting means provided in the first space so as to face the rotating disk and pushing or pulling the rotating disk to one side according to the measurement result of the measuring means;
An operation unit for receiving a measurement result of the measurement unit, which is measured by the measurement unit and removed noise through a low-pass filter, for comparing the measured reference load with a predetermined reference load;
A conversion unit that receives the comparison result of the operation unit, converts the control result into a control gain of the control unit, and performs feedback control of the control unit to cancel the thrust by outputting the control gain;
And an airfoil bearing thrust force adjusting device for adjusting an airfoil bearing thrust force for the turbo compressor.
delete The method according to claim 1,
Wherein the measuring means is a load cell or a displacement sensor.
The method according to claim 1,
Wherein the adjusting means comprises a hybrid magnet formed by mixing an electromagnet or an electromagnet and a permanent magnet.







KR1020150130553A 2015-09-15 2015-09-15 thrust control apparatus for air foil bearing of turbo compressor KR101803058B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020150130553A KR101803058B1 (en) 2015-09-15 2015-09-15 thrust control apparatus for air foil bearing of turbo compressor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020150130553A KR101803058B1 (en) 2015-09-15 2015-09-15 thrust control apparatus for air foil bearing of turbo compressor

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KR101803058B1 true KR101803058B1 (en) 2017-11-29

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CN108534940B (en) * 2018-05-14 2020-06-19 西安交通大学 Device and method for measuring axial force of rotor of double-screw compressor

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014231826A (en) * 2013-05-30 2014-12-11 三菱重工業株式会社 Turbo compressor and turbo refrigerator using the same

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Publication number Priority date Publication date Assignee Title
KR20090062075A (en) 2007-12-12 2009-06-17 (주) 진솔터보기계 Device for controlling thrust of turbo-compressor

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014231826A (en) * 2013-05-30 2014-12-11 三菱重工業株式会社 Turbo compressor and turbo refrigerator using the same

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