KR20240002788A - Turbomachinery Having A Longer Lifespan - Google Patents

Abstract

A long-life turbomachine is disclosed. The turbomachine is equipped with air bearings (3, 4) for supporting a rotor (21) and electromagnets (30, 40) for providing buoyancy to the front end or both ends of the rotor (21). When the turbomachine is stationary, the electromagnets (30, 40) operate when the turbomachine starts and brakes to reduce wear and deformation of the air bearings (3, 4). The life of the air bearings (3, 4) is extended, and the operational stability and reliability of the turbomachine are improved.

Description

Turbomachinery Having A Longer Lifespan}

The present invention relates to turbo machines, especially long-life turbo machines capable of reducing wear and fatigue of air bearings.

Turbo devices that transfer energy between the rotor and fluid, such as turbo blowers and turbo compressors, are known. A turbo blower blows air at high speed using the rotational force of an impeller coupled to a rotor. Turbo blowers are widely used in industrial sites that require blowing pressurized air, such as aeration facilities in sewage or wastewater treatment plants and powder transport. Turbo compressors produce high-pressure compressed air.

The rotor of a turbo machine is supported in contact with ball bearings, or non-contactly supported with air bearings or magnetic bearings. Non-contact bearings do not require lubricant and have low friction and noise, making them suitable for supporting the rotor of high-speed turbo machines. Air bearings levitate the rotor by an air film built up between the rotating rotor. The air bearing has an elastic bump foil and a top foil covering the bump foil.

Air bearings do not contact the rotor during high-speed rotation under normal conditions. However, problems arise in the process from a standstill to the rotor being lifted (starting process), and in the process from the rotor being lifted to a stop (braking process). For example, during starting and braking, the rotor rotates below the critical rotational speed for lifting the rotor, which causes the air bearings to contact the rotor and wear out, shortening its lifespan. Also, when the operation is stopped, the air bearing is pressed down under the load of the rotor. Such contact with the rotor causes wear and fatigue of the air bearing, and eventually deforms and damages the air bearing.

Air bearings that are significantly deformed or damaged cannot support the rotor normally. For example, if one of the journal bearings on both ends of the rotor is severely deformed or damaged, the rotor will behave abnormally and cause vibration. In severe cases, the impeller may hit the impeller housing and be damaged. If the damage to the air bearing is severe, or if the damage increases due to repeated maneuvering attempts, the impeller may be damaged to the point where it can no longer be used.

To prevent damage to the impeller or rotor, if the rotor exhibits abnormal behavior, the turbo machine is immediately controlled to braking mode. Air bearings theoretically have a semi-permanent lifespan when operated continuously without stopping the motor, but when applied to processes that require frequent operation stops, the lifespan reduction due to wear and fatigue mentioned above cannot be avoided. Technologies to improve the durability of air bearings, such as applying lubrication and anti-wear coatings, are sometimes applied, but they have limitations. In the case of a heavy rotor, mechanical friction with the air bearing is greater in proportion to its weight, so a decrease in the lifespan of the air bearing becomes a further problem. Air bearings, which are applied to processes with frequent stops and starts, are ranked high among turbo equipment repair items and have a relatively short replacement cycle. Since replacement requires stopping the turbo equipment in the process, there is a high demand for extending the life of air bearings in industrial sites with applicable operating conditions.

Magnetic bearings can be considered as an alternative to air bearings, which have limited service life. Magnetic bearings levitate the rotor by electromagnetic force, so there is no risk of damage due to contact or friction with the rotor during starting and braking. However, in order to measure the circumferential and axial positions of the rotor at ultra-high speed and control its behavior following the complex and dynamic behavior of a high-speed rotor that rotates tens of thousands of times per minute, a complex system that integrates expensive electric, electronic, and control technologies is required. This is required. Compared to air bearings, which have a mechanical and simple structure, magnetic bearings have the disadvantage of having a limited scope of industrial application because they require tens of times higher costs.

The matters described above are only intended to enhance understanding of the background of the present invention, and should not necessarily be taken as an acknowledgment that the matters described are already publicly known or constitute general knowledge in this technical field.

The present invention is based on the recognition of the above prior art, and seeks to provide a long-life turbo machine that can reduce or delay wear, fatigue, or deformation of air bearings.

The present invention seeks to provide a long-life turbo machine that can extend the replacement cycle and life of air bearings.

The present invention seeks to provide a long-life turbo machine with high stability and reliability during operation by reducing wear and damage of air bearings.

The present invention seeks to provide a long-life turbo machine that can reduce sudden damage to air bearings due to fatigue accumulation, etc., and damage to rotor parts, including the impeller, resulting from this.

The problems to be solved by the present invention are not necessarily limited to the matters mentioned above, and other problems not yet mentioned may also be understood by the matters described below.

A long-life turbo machine according to the present invention to achieve the above object includes a rotor and a stator installed in a casing, and an impeller connected to the front end of the rotor.

Characteristically, the long-life turbo machine according to the present invention includes front and rear bearing housings for radially supporting the rotor, and an airfoil journal bearing is interposed between these bearing housings and the rotor; a ferromagnetic thrust runner disposed axially opposite the front bearing housing and extending radially from the rotor, with a thrust bearing interposed between the thrust runner and the front bearing housing; and a front electromagnet provided to pull the thrust runner from above and provide a lifting force to the front end of the rotor. Using a front electromagnet, it is possible to prevent or reduce wear and damage to the front airfoil journal bearing due to the load applied at the front end of the rotor, especially due to the heavy impeller.

According to an embodiment of the present invention, the turbo device includes a ferromagnetic ring provided at the rear end of the rotor and surrounding the rotor; And it further includes a rear electromagnet provided to provide a lifting force to the rear end of the rotor by pulling the ferromagnetic ring from above. Control of the operation of the front and rear electromagnets prevents wear and damage to the front and rear airfoil journal bearings in contact with the rotor.

According to an embodiment of the present invention, a turbo machine includes an inverter for driving the rotor and a controller for controlling the inverter. The controller is configured to lift the rotor by operating the front electromagnet or both the front and rear electromagnets when the rotor is at rest, when starting, and when braking.

According to an embodiment of the present invention, the front and rear electromagnets include an arc-shaped yoke; Legs extending from the inner peripheral surface of the yoke toward the rotor; and a coil wound around the leg. The yoke is fixed to the casing, and the electromagnet may be composed of two or more parts. This electromagnet can be installed in a narrow space within the turbo equipment housing.

According to an embodiment of the present invention, the casing is provided at the front end and includes an outer flange for coupling the impeller housing to the front thereof; and an inner flange spaced apart from the rear of the outer flange. The front electromagnet and the thrust runner are arranged to face each other in the radial direction between the outer flange and the inner flange, and the yoke of the front electromagnet is fixed to the casing by a fastening member inserted from the outer flange to the inner flange. According to this, it is convenient to fix the front electromagnet to the casing during the turbo equipment assembly process, and space utilization is high.

According to an embodiment of the present invention, the front bearing housing includes a sleeve facing the rotor; and a riser extending radially outward from the sleeve. The riser of the front bearing housing is interposed between the thrust runner and the inner flange, and has a communication hole extending through the inner flange and the riser toward the front electromagnet. Cooling air flows into the front electromagnet through this communication hole.

According to an embodiment of the present invention, the turbo machine further includes a rear support coupled to the rear bearing housing at the rear of the rear bearing housing. The rear bearing housing includes a sleeve facing the rotor; and a riser extending radially outward from the sleeve. Between the rear bearing housing and the rear support, the rear electromagnet and the ferromagnetic ring are arranged to face each other in the radial direction, and the yoke of the rear electromagnet is fixed to the riser of the rear bearing housing. According to this, it is convenient to fix the front electromagnet to the casing during the turbo equipment assembly process, and space utilization is high.

According to the present invention as described above, wear, fatigue, or deformation of air bearings, especially airfoil journal bearings, that are subject to the load of the rotor and impeller can be reduced or delayed. Wear and deformation of air bearings are especially problematic when the rotor is at rest, when starting, and when braking. In these situations, damage to air bearings can be prevented or reduced by using electromagnets.

According to the present invention, it is possible to extend the replacement cycle and lifespan of air bearings.

According to the present invention, it is possible to reduce wear and damage of air bearings, thereby increasing stability and reliability during turbo machine operation.

According to the present invention, sudden damage to air bearings due to fatigue accumulation, etc., and impeller damage resulting from this can be reduced.

Figure 1 shows a schematic cross-section of a turbo machine according to an embodiment of the present invention.
Figure 2 shows an electromagnet according to an embodiment of the present invention.
Figure 3 shows an electromagnet according to another embodiment of the present invention.
Figure 4 shows a schematic cross-section of a turbo device according to another embodiment of the present invention.
Figure 5 shows the components of a turbo machine according to an embodiment of the present invention.

Hereinafter, we will look at examples in more detail so that we can understand various characteristic aspects of the present invention. In the drawings, identical or equivalent components may be indicated by the same symbols, and the drawings may be exaggerated or schematically shown for intuitive understanding of the features of the present invention.

In this document, unless otherwise specified or inherently impermissible, expressions to describe the relationship between two elements, such as 'phase' and 'connection', refer to the two elements being in direct contact with each other. Of course, a third element is allowed to be inserted between the first and second elements. Directional indications such as front and back, left and right, or up and down are only for convenience of explanation.

1 schematically shows a cross section of a turbo blower as an example of a turbo device according to an embodiment.

Referring to FIG. 1, the turbo blower includes a casing 10, high-speed motors 21 and 22 built into the casing 10, and an impeller 1 in front of the high-speed motors 21 and 22. In Figure 1, the volute housing surrounding the impeller 1 is omitted.

The casing 10 includes a cylindrical body surrounding the high-speed motors 21 and 22, and a rear cover 18 coupled to the rear end of the body. The body may be manufactured in one piece or may be an assembly of several parts. The rear cover 18 is provided with a central hole through which external air flows in to cool the high-speed motors 21 and 22. Inlet holes for external air for cooling the high-speed motors 21 and 22 may be provided at other locations in the casing 10.

The high-speed motors 21 and 22 include a rotor 21 installed in the front and rear directions and a stator 22 fixed to the casing 10. A gap is provided between the rotor 21 and the stator 22 to allow rotation of the rotor 21. The rotor 21 has a magnet, and the stator 22 has a coil 22a for rotating the rotor 21. A cooling passage 23 extends on the outer peripheral surface of the stator 22 in the longitudinal direction of the rotor 21.

The impeller 1 is coupled to the front end of the rotor 21, specifically the front end of the tie bolt 27. The air sucked in from the outside by the rotational force of the impeller 1 is pressurized while flowing along the flow path of the volute housing and is blown to the outside at high speed. An intake duct may be provided at the center front of the volute housing to guide the sucked air toward the impeller (1).

The cooling fan 5 is mounted on the rear end of the rotor 21, specifically, on the tie bolt 27 at the rear end of the rotor 21. The cooling fan 5 rotates together with the rotor 21 and introduces external air into the casing 10 to cool the heat generated by the high-speed motors 21 and 22 during operation. When the cooling fan (5) rotates, external air flows into the casing (10) through the inflow passage (16), into the cooling passage (23) on the outer peripheral surface of the stator (22), and the gap between the rotor (21) and the stator (22). is supplied by

The air bearing of the turbo blower includes airfoil journal bearings (3, 4) and thrust bearings (2).

Airfoil journal bearings 3 and 4 support both ends of the rotor 21 in the radial direction. Front and rear bearing housings 11 and 13 are provided at the front and rear of the stator 22 for installation of airfoil journal bearings 3 and 4. These bearing housings 11 and 13 are fixed to the casing 10 and allow the rotor 21 to rotate. Airfoil journal bearings 3 and 4 are interposed between the bearing housings 11 and 13 and the rotor 21. Both ends of the rotor 21 are supported in the radial direction, that is, in a direction perpendicular to the rotation axis of the rotor 21, by the airfoil journal bearings 3 and 4.

A disk-shaped thrust runner 24 extending radially from the rotor 21 is provided at the front end of the rotor 21. A front bearing housing 11 is disposed at the rear of the thrust runner 24 to face the thrust runner 24 in the axial direction, and a bearing support 12 is disposed in front of the thrust runner 24. An airfoil thrust bearing (2) is interposed between the bearing support (12) and the thrust runner (24), and between the front bearing housing (11) and the thrust runner (24), respectively. The rotor 21 is axially supported by the thrust bearing 2.

While rotating smoothly in a normal state, the rotor 21 is supported non-contactly by an air film built up between the air bearings 2, 3, and 4. However, when the high-speed motor (21, 22) is at a standstill, starting, and braking, there is physical contact, sometimes violent contact, or collision between the rotor (21) and the air bearings, especially the journal bearings (3, 4). This happens. This physical contact causes wear and deformation of the air bearings (3, 4) and shortens their lifespan, which shortens the inspection cycle of the turbo device for inspection and replacement of the air bearings (3, 4). If these inspections are overlooked, major damage to major parts of the turbocharger may occur.

Electromagnets 30 and 40 are installed on both ends of the rotor 21 of the turbo blower. The electromagnets 30 and 40 prevent or reduce damage to the air bearings 3 and 4 due to the load of the rotor 21 when the motor stops, starts, and brakes. Since the electromagnets (30, 40) do not need to be operated when the turbo blower is in normal operation, a complex algorithm design or absolute value is required considering the rotational speed and aspect of the rotor (21), the lift force by the air bearings (3, 4), etc. Precision sensing, etc. is not required.

If it has been decided to utilize the electromagnets 30 and 40 even if they operate relatively or absolutely less sensitively and less precisely as described above, how can the electromagnets 30 and 40 be installed in a more cost-effective and space-efficient manner? The problem remains. Specific solutions according to embodiments are described below.

Continuing to refer to FIG. 1, a front electromagnet 30 is installed at the front end of the rotor 21, and a rear electromagnet 40 is installed at the rear end of the rotor 21. These electromagnets 30 and 40 are fixed to the casing 10 above the rotor 21 so as to lift the rotor 21 by pulling the rotor 21 from above (attractive force).

The front end of the casing 10 is provided with an outer flange 15 extending radially outward and an inner flange 17 behind the outer flange 15. The inner flange 17 extends radially inward, and the inner flange 17 and the outer flange 15 are spaced apart from each other so that a gap exists between them. The outer flange 15 is bolted to the volute housing disposed in front of it.

The front electromagnet 30 is disposed in the gap between the outer flange 15 and the inner flange 17. The front electromagnet 30 is disposed to face the thrust runner 24 on the radial outer side of the thrust runner 24, and the thrust runner 24 is ferromagnetic so that it can be pulled by electromagnetic attraction from the front electromagnet 30. It is made from material. The ferromagnetic material may be selected from economical and excellent processability materials that contain iron (Fe), for example.

The front electromagnet 30 is fixed to the casing 10 by a fastening member b1 inserted from the outer flange 15 to the inner flange 17. Before the impeller 1 and rotor 21 are assembled, the front and rear electromagnets 30 and 40 are assembled into the casing 10. During the turbo machine assembly process, the front electromagnet 30 can be easily assembled to the casing 10 by the fastening member b1.

A ferromagnetic thrust runner (24) is disposed between the front bearing housing (11) and the bearing support (12). The front bearing housing 11 includes a sleeve 11a surrounding the rotor 21, and a riser 11b extending radially outward from the sleeve 11a at the front end of the sleeve 11a and facing the thrust runner 24. Equipped with An airfoil journal bearing 3 is disposed between the sleeve 11a and the rotor 21, and an airfoil thrust bearing 2 is disposed between the riser 11b and the thrust runner 24.

The upper end of the riser (11b) of the front bearing housing (11) is tightly coupled to the inner flange (17). A communication hole (7) extending through the inner flange (17) and the riser (11b) toward the front electromagnet (30) is provided. Cooling air flowing into the casing (10) through the communication hole (7) through the cooling fan (5) is supplied to the front electromagnet (30).

The rear bearing housing 13 includes a sleeve 13a surrounding the rotor 21, a riser 13b extending radially outward from the sleeve 13a at the rear end of the sleeve 13a, and a rotor 21 from the riser 13b. ) It has a cylindrical outer wall extending in the longitudinal direction (front). An inflow passage 16 is provided between the outer wall and the casing 10. A journal airfoil bearing 4 is interposed between the rotor 21 and the sleeve 13a.

A rear support 14 is disposed at the rear of the rear bearing housing 13. A mounting space (S) is provided between the rear bearing housing (13) and the rear support (14), and the rear electromagnet (40) is placed in this mounting space (S). The rear support 14 is fixed to the rear bearing housing 13 by a fastening member b3. An inflow passage 16 is provided between the rear support 14 and the rear cover 18.

The rear electromagnet 40 is fixed to the rear bearing housing 13 by a fastening member b2 inserted into the rear bearing housing 13 from the rear. The rear bearing 13 is fixed to the casing 10. After the rear bearing housing 13 is mounted on the casing 10, the rear electromagnet 40 is mounted on the rear bearing housing 13, and the rear support 14 is fixed to the rear bearing housing 13.

A ferromagnetic ring 25 surrounding the rotor 21 is installed at the rear end of the rotor 21. The rear electromagnet 40 is disposed to face the ferromagnetic ring 25 on the radial outer side of the ferromagnetic ring 25 so as to pull the ferromagnetic ring 25 from above and provide a lifting force to the rear end of the rotor 21.

2 and 3 show electromagnets 30 and 40 according to an embodiment. 2 and 3 are views of the electromagnets 30 and 40 as seen in the axial direction of the rotor 21.

2 and 3, the electromagnets 30 and 40 include arc-shaped yokes 31 and 41, and legs 32 and 42 around which coils 33 and 43 are wound. The legs 32 and 42 extend from the radial inner sides of the yokes 31 and 41 toward the rotor 21 (or extend radially toward the center, or toward the center of the yoke curvature). A plurality of legs 32 and 42 are provided on the yokes 31 and 41. The ends of the legs 32 and 42 are arranged along the circumferential direction of the rotor 21 and have a constant distance from the rotor 21. The yokes 31 and 41 extend along the trajectories of large concentric circles, and the ends of the legs 32 and 42 are arranged along the trajectories of small concentric circles.

The electromagnets 30 and 40 are composed of a plurality of parts (see FIG. 2) or integrally (see FIG. 3).

Referring to Figure 2, the front electromagnet 30 is composed of two electromagnet parts 30a and 30b arranged in the circumferential direction. The yoke 31 of the front electromagnet 30 is inserted into the gap between the outer flange 15 and the inner flange 17, and has a fastening hole 35 for inserting the fastening member b1 arranged in the circumferential direction. The yoke 31 is fixed to the casing 10 by the fastening member b1. On the radial inner side of the yoke 31, a leg 32 extends toward the radial center of the rotor 21, that is, in the direction of the rotation axis. The tip of the leg 32 faces the ferromagnetic thrust runner 24. The thrust runner 24 extends along the circumference of the rotor 21 in a direction perpendicular to the axis of the rotor 21. The distance between the ends of the legs 32 and the thrust runner 24 is constant. When power is applied to the coil 33, the ferromagnetic thrust runner 24 is attracted to the front electromagnet 30 by electromagnetic force.

Referring to FIG. 3, the rear electromagnet 40 is formed as one piece. The yoke 41 of the rear electromagnet 40 is fixed to the rear bearing housing 13 and has a fastening hole 45 for inserting a fastening member b2 arranged in the circumferential direction. A leg 42 extends on the radial inner side of the yoke 41 in the direction of the rotation axis of the rotor 21. The tip of the leg 42 faces the ferromagnetic ring 25 surrounding the rotor 21. The distance between the ends of the legs 42 and the ferromagnetic ring 25 is constant. When power is applied to the coil 43, the ferromagnetic ring 25 is attracted to the rear electromagnet 40 by electromagnetic force.

Since the heavy impeller 1 is coupled to the front end of the rotor 21, the load on the front end of the rotor 21 is greater than the load on the rear end of the rotor 21. This means that a greater load is applied to the front airfoil journal bearing (3) than to the rear airfoil journal bearing (4), and that the life of the front journal bearing (3) may be shorter than that of the rear journal bearing (4). it means. To solve this problem of asymmetric life between the front journal bearing 3 and the rear journal bearing 4, the front electromagnet 30 is designed to provide a greater attractive force than the rear electromagnet 40.

Figure 4 shows a turbo device according to another embodiment. The turbo device according to this embodiment is a turbo blower and is configured mostly the same as the turbo blower described above. Avoid duplicate descriptions of the same components.

Referring to FIG. 4, in the turbo blower of this embodiment, the front electromagnet 30 is installed at the front end of the rotor 21, and the rear electromagnet 40 is not installed. The front electromagnet 30 is inserted into the gap between the outer flange 15 and the inner flange 17 and is fixed by the fastening member b1.

As previously mentioned, a greater load is applied to the front side of the rotor 21 to which the impeller 1 is connected than to the rear side of the rotor 21. Using the front electromagnet 30, excessive load applied to the front airfoil journal bearing (3) can be reduced at the front end of the rotor (21), thereby reducing the gap between the front and rear journal bearings (3, 4). The lifespan discrepancy can be resolved. The difference in life between the front and rear journal bearings (3, 4) is a factor that shortens the inspection and replacement cycle of the air bearings (3, 4). As the number of times the turbo blower is stopped, the possibility and extent of damage to the air bearings (3, 4) increases, so eliminating the above lifespan deviation helps extend the life of the air bearings (3, 4) and the turbo device.

Meanwhile, in the past, an impeller 1 made of aluminum was used to reduce weight. In normal operating conditions, the rotating rotor 21 is supported by an air film, so the possibility of damage to the air bearings 3 and 4 is not high in normal operating conditions. The problem is during stopping, starting, and braking. In these cases, if the lifespan of the air bearings (3, 4) can be guaranteed, the impeller (1) can be made of a material with lower cost and excellent processability even if the weight increases slightly. It is advantageous from a cost-economic perspective. Even if a slightly heavier impeller (1) is used than before, the front end of the rotor (21) can be lifted using the front electromagnet (30) to reduce the excessive load applied to the front airfoil journal bearing (3). Through this, the life difference between the front and rear journal bearings 3 and 4 can be resolved.

A sensor 19 is installed in the rear cover 18 to detect the rotation of the rotor 21. The rear end of the rear tie bolt (27b) is exposed through the central hole of the rear cover (18), and the sensor 19 measures the rotational state of the rear tie bolt (27b) and transmits it to the controller.

Figure 5 shows turbomachinery components for explaining the control of the electromagnets 30 and 40. According to the embodiment, this turbo device is a turbo blower employing a high-speed permanent magnet synchronous motor (PMSM) driven by an inverter.

Referring to Figure 5, the turbo blower is equipped with an inverter 8 for driving high-speed motors 21 and 22, a speed sensor 19, electromagnets 30 and 40, and a controller 9 for controlling them. . The rotational speed of the rotor 21 can be calculated using the output voltage of the inverter 8. It is simpler to use the speed sensor (19) than to use a complex algorithm.

When the turbo blower start signal is received, the controller 9 uses the inverter 8 to drive the high-speed motors 21 and 22. The speed sensor 19 measures the number of rotations of the rotor 21 and transmits it to the controller 9. The controller 9 levitates the rotor 21 by applying power to the electromagnets 30 and 40 until the rotation of the rotor 21 reaches a steady state in the starting stage. The lift force can be adjusted depending on the rotation speed of the rotor 21.

When the turbo blower braking signal is received, the controller 9 gradually slows down the high-speed motors 21 and 22 using the inverter 8. The speed sensor 19 measures the number of rotations of the rotor 21 and transmits it to the controller 9, which controls the electromagnets 30 and 40 from the braking stage until the rotation of the rotor 21 stops. Apply power to levitate the rotor 21. The lift force can be adjusted depending on the rotation speed of the rotor 21.

When the rotor 21 is stopped, the controller 9 maintains power applied to the electromagnets 30 and 40 to prevent or reduce deformation of the air bearings 3 and 4 to keep the rotor 21 floating.

Embodiments of the present invention have been described above, and these embodiments will be helpful in understanding various aspects and features of the present invention. The features or elements introduced in these embodiments may be combined in various forms, and such combinations may provide another embodiment that has not yet been described in this document.

The scope of the invention sought to be protected is set forth in the claims. The elements described in the claims may be variously changed, modified, and replaced with equivalents without departing from the essence or scope of the invention. The reference numerals in the claims, if provided, are only intended to facilitate easy and intuitive understanding of the claimed inventions or their elements and do not limit the scope of the claimed inventions.

1: Impeller 2: Airfoil thrust bearing
3,4: Airfoil journal bearing 5: Cooling fan
10: Casing 11: Front bearing housing
12: Bearing support 13: Rear bearing housing
21: rotor 22: stator
24: thrust runner 25: ferromagnetic ring
30,40: electromagnet 31,41: yoke
32,42: Leg 33,43: Coil

Claims (7)

In a turbo machine including a rotor (21) and a stator (22) installed in the casing (10), and an impeller (1) axially connected to the front end of the rotor (21),
Front and rear bearing housings (11, 13) for radially supporting the rotor (21), with airfoil journal bearings (3, 4) interposed between these bearing housings (11, 13) and the rotor (21);
A ferromagnetic thrust runner 24 is disposed axially opposite the front bearing housing 11 and extends radially from the rotor 21, and a thrust bearing (24) is provided between the thrust runner 24 and the front bearing housing 11. 2) is interposed; and
A turbo machine including a front electromagnet (30) provided to pull the thrust runner (24) from above and provide a lifting force to the front end of the rotor (21). The method according to claim 1, comprising: a ferromagnetic ring (25) provided at the rear end of the rotor (21) and surrounding the rotor (21); and
A turbo device further comprising a rear electromagnet (40) provided to provide a lifting force to the rear end of the rotor (21) by pulling the ferromagnetic ring (25) from above. The method according to claim 1 or 2, further comprising an inverter (8) for driving the rotor (21) and a controller (9) for controlling the inverter (8),
The controller 9 operates the front electromagnet 30 or the front and rear electromagnets 30 and 40 when the rotor 21 is at a standstill, at least when starting, and when braking. A turbo device configured to boost . The method according to claim 1 or 2, wherein the front and rear electromagnets (30, 40) are,
arc-shaped yoke (31);
A leg 32 extending from the inner peripheral surface of the yoke 31 toward the rotor 21; and
A turbo machine comprising a coil (33) wound around the leg (32) and a yoke (31) fixed to the casing (10). The method according to claim 4, wherein the casing (10) is provided at the front end and includes an outer flange (15) for coupling the impeller housing to the front thereof; and an inner flange (17) spaced apart from the rear of the outer flange (15).
The front electromagnet 30 and the thrust runner 24 are arranged to face each other in the radial direction between the outer flange 15 and the inner flange 17, and the yoke 31 of the front electromagnet 30 is separated from the outer flange 15. A turbo device fixed to the casing (10) by a fastening member (b1) inserted into the inner flange (17). The method according to claim 5, wherein the front bearing housing (11) includes a sleeve (11a) facing the rotor (21); and a riser (11b) extending radially outward from the sleeve (11a),
The riser 11b of the front bearing housing 11 is interposed between the thrust runner 24 and the inner flange 17, and extends toward the front electromagnet 30 through the inner flange 17 and the riser 11b. A turbo device having a communication hole (7). The method according to claim 4, further comprising a rear support (14) coupled to the housing (13) at the rear of the rear bearing housing (13),
The rear bearing housing 13 includes a sleeve 13a facing the rotor 21; and a riser (13b) extending radially outward from the sleeve (13a),
A rear electromagnet 40 and a ferromagnetic ring 25 are arranged to face each other in the radial direction between the rear bearing housing 13 and the rear support 14, and the yoke 41 of the rear electromagnet 40 is connected to the rear bearing housing 13. ) Turbo device fixed to the riser (13b).

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