Turbocompressor

Abstract

The invention discloses a turbo compressor. The rotating shaft is rotatably mounted inside the cover body. A bearing rotatably supports the rotating shaft. The bearing housing is coupled to the housing and supports the bearing. The bearing comprises a radial bearing and a radial bearing safety device. The radial bearing is mounted on an inner circumferential surface of the bearing housing and has a gas foil bearing to support a radial load of the rotating shaft. The radial bearing safety device is arranged on the bearing cover body, and the radial moving distance of the rotating shaft is limited within the elastic deformation range of the radial bearing. According to the structure, the radial bearing can be prevented from being damaged.

Description

Technical Field

[0001] The invention relates to a turbo compressor having a safety device for a bearing. Background Art

[0002] Generally, a compressor is widely used in household appliances or the entire industry. It is a device that receives power from a power generating device such as an electric motor or a turbine to compress air or a refrigerant or other various working gases.

[0003] The compressor includes a turbo compressor. A turbo compressor converts a part of velocity energy into pressure energy by applying centrifugal force by rotating an impeller (hereinafter referred to as an impeller) at high speed, thereby compressing a working gas.

[0004] For example, a turbo compressor may be used in a cooling system for supplying cold water to a demand side, wherein the cooling system cools the cold water by exchanging heat between a refrigerant circulating in a refrigerant cycle and cold water circulating at the demand side.

[0005] On the other hand, in Korean Patent Publication No. 10-1746896 (hereinafter, Patent Document 1), an exhaust turbocharger having a means for fixing the shaft in the axial direction when the compressor wheel is broken is disclosed.

[0006] Patent Document 1 is an invention relating to a fixing ring for fixing a rotating shaft in the axial direction when a compressor turbine or an impeller is damaged.

[0007] According to the invention of Patent Document 1, when the compressor turbine and impeller are damaged, the parts may be damaged and scattered to the outside of the cover. In order to solve the problem of difficulty in disassembly, the fixing ring is a structure that fixes the shaft axially when the impeller and turbine are damaged to prevent the shaft from detaching and make disassembly and assembly easier.

[0008] However, since Patent Document 1 requires additional assembly of components such as a fixing ring and a fixing cover, there is a problem of an increase in the number of components and an increase in manufacturing cost.

[0009] In addition, there is a problem in that it is difficult to align the fixing ring and the shaft when assembling the fixing ring.

[0010] On the other hand, a multi-stage turbo compressor can compress the refrigerant multiple times using multiple impellers and multiple guide vanes. At this time, as the number of compressions increases, the pressure of the refrigerant rises.

[0011] For example, a primary impeller may be installed on one side of the rotating shaft, and a secondary impeller may be installed on the other side of the rotating shaft.

[0012] A pressure difference is generated between the refrigerant sucked into the first-stage impeller and the refrigerant sucked into the second-stage impeller.

[0013] Therefore, different axial loads are applied to both ends of the rotating shaft of the compressor, and the axial load acts from the secondary compression part (including the impeller and the guide vane) with a larger axial load toward the primary compression part with a relatively smaller axial load.

[0014] Therefore, there is a problem that the axial eccentric load acting on the rotating shaft causes damage to the thrust bearing supporting the axial load.

[0015] In particular, when liquid refrigerant is sucked into the impeller, it will seriously affect the bearing damage problem.

[0016] Korean Patent No. 10-0253247 (hereinafter, Patent Document 2) discloses a thrust bearing structure of a turbo compressor.

[0017] Patent document 2 is constructed so that a part of the refrigerant gas discharged to the refrigeration cycle device through the first compression chamber and the second compression chamber in the closed container provided with a driving part is bypassed toward the back side of the first impeller and the second impeller, thereby utilizing the thrust of the inflowing refrigerant gas to support the axial direction of the drive shaft.

[0018] For example, the force pushed by the suction force on the first impeller during the first compression of the compressed gas is offset by the compressed gas flowing into the back side of the first impeller. Conversely, the force pushed by the suction force on the second impeller during the second compression of the compressed gas is offset by the compressed gas flowing into the back side of the second impeller. Ultimately, the two impellers will not deviate in any axial direction of the drive shaft.

[0019] However, in Patent Document 2, in order to allow a portion of the refrigerant gas discharged from the second compression chamber to bypass the back sides of the first impeller and the second impeller, it is necessary to set a first retention tank, a second retention tank, a first bypass pipe and a second bypass pipe outside the turbo compressor. As a result, there is a problem that the structure of the compressor becomes complicated and a large amount of compressor installation space is occupied. Summary of the invention

[0020] Problems to be solved by the invention

[0021] A first object of the present invention is to provide a turbo compressor capable of minimizing damage to a radial bearing even when the radial bearing is subjected to an external impact exceeding the elastic deformation range of the radial bearing.

[0022] A second object of the present invention is to provide a turbo compressor that does not require additional assembly parts and can reduce the number of parts and manufacturing costs.

[0023] A third object of the present invention is to provide a turbo compressor with a simple structure.

[0024] A fourth object of the present invention is to provide a turbo compressor having a structure that is easy to assemble and disassemble.

[0025] A fifth object of the present invention is to provide a turbo compressor having a structure that facilitates alignment between a radial bearing and a shaft.

[0026] A sixth object of the present invention is to provide a turbo compressor capable of minimizing damage to a thrust bearing when a high-pressure refrigerant or a liquid refrigerant flows into a guide vane and generates a large axial load.

[0027] A seventh object of the present invention is to provide a turbo compressor capable of minimizing the amount of liquid refrigerant flowing into a guide vane.

[0028] An eighth object of the present invention is to provide a turbo compressor having a simple structure and capable of minimizing the installation space.

[0029] A ninth object of the present invention is to provide a turbo compressor having a structure that facilitates alignment between a thrust bearing and a shaft.

[0030] Technical solutions to the problem

[0031] As a result of intensive research by the present inventors, the above-mentioned first to ninth purposes of the present invention can be achieved by the following embodiments of the present invention.

[0032] (1) A turbo compressor according to an embodiment of the present invention includes: a cover; a rotating shaft rotatably mounted inside the cover; an impeller coupled to the rotating shaft and rotating; a bearing supporting the rotating shaft so as to be rotatable; a bearing cover coupled to the cover and supporting the bearing; the bearing including: a radial bearing having an air foil bearing mounted on the inner circumferential surface of the bearing cover and surrounding the rotating shaft and separated from the rotating shaft by an air gap to support the radial load of the rotating shaft; and a radial bearing safety device disposed on the bearing cover to limit the radial movement distance of the rotating shaft within the elastic deformation range of the radial bearing. According to such a configuration, the radial bearing safety device limits the radial movement range of the rotating shaft within the elastic deformation range of the radial bearing, thereby preventing the radial bearing from being damaged.

[0033] (2) In the above (1), the air foil bearing includes: a bump foil including a plurality of curved surface portions protruding toward the rotating shaft and a connecting portion connecting the plurality of adjacent curved surface portions; and a cover foil configured to cover the inner side of the bump foil. According to such a configuration, even without oil, the air foil bearing can function as a radial bearing by using a working fluid during high-speed rotation, that is, effectively supporting the radial load of the rotating shaft, and realizing a frictionless and efficient compressor.

[0034] (3) In the above (1), the radial bearing safety device includes a stopper formed to protrude from the inner circumferential surface of the bearing cover toward the rotating shaft. According to such a configuration, the stopper protrudes from the inner circumferential surface of the bearing cover and is formed integrally, so there is no need to assemble an additional component for preventing the radial bearing from being damaged. Therefore, the number of components and the number of assembly steps can be reduced, and this also greatly contributes to reducing manufacturing costs.

[0035] (4) In the above (3), the limiter can be formed by extending in the circumferential direction along the inner peripheral surface of the bearing cover. According to such a structure, as the limiter is separated from the rotating shaft by an air gap in a closed loop form and surrounds the rotating shaft, even when the rotating shaft moves abnormally due to an external impact, it is possible to prevent the radial bearing from being damaged in all directions in the radial direction.

[0036] (5) In the above (3), the radial bearing further includes a wave-preventing ring, which is arranged on one side of the air foil bearing to prevent the air foil bearing from axially disengaging, and the air foil bearing can be arranged between the wave-preventing ring and the stopper. According to such a configuration, not only can the wave-preventing ring be used to prevent the radial bearing from axially disengaging, but the stopper can also be used to prevent the radial bearing from contacting the rotating shaft and being damaged.

[0037] (6) In the above (5), the air foil bearing includes a corrugated foil having a curved portion protruding toward the rotating shaft, the corrugated foil having a wave height from the inner circumferential surface of the bearing cover body to the radial inside to the vertex of the curved portion, and the protruding height of the stopper is lower than the wave height and higher than the height of the corrugated anti-slip ring protruding toward the rotating shaft with the inner circumferential surface of the bearing cover body as a reference. According to such a configuration, the stopper can prevent the rotating shaft from being damaged due to the contact between the rotating shaft and the corrugated anti-slip ring when the rotating shaft moves radially.

[0038] (7) In the above (3), the limiting portion may include: a first limiting portion, which is arranged on one axial side of the radial bearing; and a second limiting portion, which is arranged on the other axial side of the radial bearing. According to such a configuration, the limiting portion can not only prevent the radial bearing from being damaged, but also prevent the radial bearing from being axially disengaged.

[0039] (8) In the above (1), the air foil bearing includes a corrugated foil having a curved portion protruding toward the rotating shaft, the corrugated foil having a wave height from the inner circumferential surface of the bearing cover body toward the radial inside to the vertex of the curved portion, and the radial bearing safety device includes a stopper protruding from the inner circumferential surface of the bearing cover body toward the rotating shaft, and the protruding height of the stopper is lower than the wave height. According to such a configuration, the stopper allows elastic deformation of the radial bearing and can prevent plastic deformation of the radial bearing.

[0040] (9) In the above (8), preferably, the protruding height of the stopper is in the range of 40 to 50% of the wave height. According to such a configuration, the protruding height of the stopper can be in the optimal range for simultaneously allowing elastic deformation of the radial bearing and preventing plastic deformation of the radial bearing.

[0041] (10) In the above (3), the stopper has an outer surface formed with a wear-resistant coating. Thus, even if the stopper contacts the rotating shaft, damage to the rotating shaft can be prevented.

[0042] (11) In the above (1), the radial bearing safety device may include: a ring installation groove, which is formed in a circumferential direction on the inner circumferential surface of the bearing cover; and a stop ring, which extends in the circumferential direction to surround the rotating shaft and separate the rotating shaft from the rotating shaft by an air gap, and the stop ring is installed in the ring installation groove. According to such a configuration, the stop ring as another embodiment of the radial bearing safety device can not only prevent the plastic deformation of the radial bearing, but also be easy to assemble to the inner circumferential surface of the bearing cover and easy to disassemble from the inner circumferential surface of the bearing cover.

[0043] (12) In the above (11), the stop ring may include: a first stop ring, which is arranged on one axial side of the radial bearing; and a second stop ring, which is arranged on the other axial side of the radial bearing. According to such a configuration, the first stop ring and the second stop ring are respectively arranged on one axial side and the other axial side of the radial bearing, thereby preventing not only the radial bearing from being damaged but also the radial bearing from being detached from the radial bearing in the axial direction.

[0044] (13) In the above (1), the radial bearing safety device includes: a plurality of ball receiving grooves formed concavely on the inner circumferential surface of the bearing cover; and a plurality of ball bearings arranged circumferentially spaced from the rotating shaft with an air gap, and mounted in the ball receiving grooves. According to such a configuration, the ball bearing as another embodiment of the radial bearing safety device can not only prevent plastic deformation of the radial bearing, but also be easily assembled to and disassembled from the inner circumferential surface of the bearing cover.

[0045] (14) In the above (1), the radial bearing safety device may include: a plurality of needle roller receiving grooves formed concavely on the inner circumferential surface of the bearing cover; and a needle roller bearing, which is separated from the rotating shaft by an air gap and arranged in the circumferential direction and installed in the needle roller receiving groove. According to such a configuration, the needle roller bearing as another embodiment of the radial bearing safety device can not only prevent the plastic deformation of the radial bearing, but also be easy to assemble to the inner circumferential surface of the bearing cover and easy to disassemble from the inner circumferential surface of the bearing cover.

[0046] (15) In the above (1), a thrust mirror plate protruding radially from the rotating shaft is further included, and the bearing may further include a thrust bearing having an air foil bearing arranged with an air gap between the thrust mirror plate and the thrust mirror plate to support the axial load of the rotating shaft. Thus, the thrust bearing supports the axial load of the rotating shaft, and thus can stably support the rotating shaft together with the radial bearing when rotating at high speed.

[0047] (16) In the above (1), it includes: an impeller housing, which accommodates the impeller and has a guide vane that extends in a spiral shape from one side of the impeller and compresses the refrigerant sucked in by the impeller; and a bypass flow path formed between the inside of the guide vane and the inside of the cover body so that a portion of the refrigerant flowing into the guide vane bypasses the inside of the cover body.

[0048] According to such a configuration, as the pressure balance is achieved between the guide vane and the cover, the difference between the pressure of the refrigerant sucked into the first impeller and the pressure of the refrigerant sucked into the second impeller can be minimized.

[0049] (17) In the above (16), the bearing includes a thrust bearing that supports the axial load of the rotating shaft, one side of the bypass flow path can be communicated with the guide vane, and the other side of the bypass flow path can be communicated with the thrust bearing.

[0050] According to such a configuration, it is possible to prevent the thrust bearing from being damaged due to the axial pressure difference between both ends of the rotating shaft.

[0051] (18) In the above (16), the bypass flow path is formed to pass through the inner side of the bearing cover, one side of the bypass flow path can be communicated with the guide vane, and the other side of the bypass flow path can be communicated with the inside of the cover.

[0052] According to such a configuration, the amount of liquid refrigerant flowing into the guide vanes can be minimized.

[0053] (19) In the above (16), the bearing cover body includes: an axial connection portion formed to surround the rotating shaft; a first radial extension portion extending radially from one side of the axial connection portion; and a second radial extension portion extending radially from the other side of the axial connection portion; the bypass flow path can be formed to pass through the first radial extension portion.

[0054] According to such a configuration, the structure of the bypass flow path can be simplified.

[0055] (20) In the above (19), the bypass flow path may include: a first bypass flow path formed through the first radially extending portion in one direction; and a second bypass flow path formed through the second radially extending portion in the one direction.

[0056] According to such a configuration, the flow channel connection between the first bypass flow channel and the second bypass flow channel is simple.

[0057] (21) In the above (20), the diameter of the second bypass flow path is greater than or equal to the diameter of the first bypass flow path.

[0058] According to such a configuration, there is a synergistic effect that the working fluid can be easily transferred from the first bypass flow path to the second bypass flow path.

[0059] (22) In the above (16), an on-off valve provided on one side of the bypass flow path and opening and closing the bypass flow path may be included.

[0060] According to such a configuration, the bypass flow path and the on-off valve are provided inside the bearing cover, so that the number of parts can be reduced and the manufacturing cost can be reduced.

[0061] (23) In the above (22), a valve connecting rod may be included, one side of which is combined with the opening and closing valve, and the other side of which is configured to be contactable and separated from the rotating shaft. When the rotating shaft moves axially, the valve connecting rod contacts the rotating shaft and transmits the power of the axial movement of the rotating shaft to the opening and closing valve.

[0062] According to such a configuration, the on-off valve is mechanically driven by contact with the axial movement of the rotating shaft, so the structure is simple and the installation space can be minimized.

[0063] (24) In the above (23), it includes: a thrust mirror plate extending radially from the rotating shaft; and a thrust bearing, which is arranged with a gap between the bearing cover and the thrust mirror plate, and has a corrugated foil and a cover foil covering the corrugated foil to support the axial load of the rotating shaft; the gap between the valve connecting rod and the thrust mirror plate can be less than or equal to the gap between the thrust bearing and the thrust mirror plate.

[0064] According to such a configuration, when the rotating shaft moves in the axial direction, the thrust mirror plate contacts the valve rod before contacting the thrust bearing, thereby effectively preventing the thrust bearing from being damaged.

[0065] (25) In the above (16), it includes: a thrust mirror plate extending radially from the rotation axis; and an opening and closing valve configured to be able to open and close the bypass flow path; the opening and closing valve may include: a valve body, a flow path opening and closing portion formed at one end to open and close the bypass flow path; a valve connecting rod connected to the other end of the valve body, when the thrust mirror plate moves axially, the valve connecting rod contacts the thrust mirror plate and transmits the axial movement power of the thrust mirror plate to the other end of the valve body; and a hinge pin, hingedly connected between one end and the other end of the valve body, playing the role of the central axis of rotation of the valve body.

[0066] According to such a structure, when the distance between one end of the valve body and the hinge pin is larger than the distance between the other end of the valve body and the hinge pin, the rotation amount of the valve body is larger than the axial movement distance of the valve connecting rod, thereby improving the responsiveness of the opening and closing valve.

[0067] (26) In the above (25), it also includes an elastic member installed on the hinge pin to restore the valve body to its original position. The elastic member can be a torsion spring that is combined with the bearing cover on one side and combined with the rotating shaft on the other side.

[0068] According to such a configuration, the torsion spring applies elastic force in the direction that hinders the rotation of the hinge pin, thereby having the advantage that the valve body can be easily moved to the original position.

[0069] (27) In the above (16), it includes: a thrust mirror plate extending radially from the rotating shaft; an opening and closing valve configured to be able to open and close the bypass flow path formed on the inner side of the bearing cover; a valve connecting rod, one side of which is combined with the opening and closing valve, and the other side is separated from the thrust mirror plate in a manner that allows selective contact; and a magnet installed on the valve connecting rod and the thrust mirror plate facing the valve connecting rod to enable the valve connecting rod to move selectively; the opening and closing valve can be opened and closed using the magnetic force of the magnet.

[0070] According to such a configuration, the on-off valve is pulled toward the thrust mirror plate by the action of the magnetic force, so that the on-off valve can be easily operated before the thrust mirror plate contacts the thrust bearing. The magnet can be applied to the valve connecting rod and the thrust mirror plate respectively, or can be selectively applied to either the valve connecting rod or the thrust mirror plate.

[0071] (28) In the above (16), it includes an on-off valve, which is configured to be able to open and close the bypass flow path formed on the inner side of the guide vane or the bearing cover body, and the on-off valve can be a differential pressure valve that works by the pressure difference between the guide vane and the inside of the cover body.

[0072] According to such a configuration, the differential pressure valve does not need to contact the thrust mirror plate, but works by utilizing the pressure difference between the guide vane and the cover body, thereby not only being able to minimize the number of parts, but also greatly contributing to the simplification of the structure. In addition, the degree of freedom of the installation position can be increased. For example, there is an advantage that the on-off valve can be easily installed at a position such as the guide vane or inside the cover body, and there are few restrictions.

[0073] (29) In the above (16), it includes an on-off valve, which is configured to be able to open and close the bypass flow path formed on the inner side of the guide vane or the bearing cover body, and the on-off valve can be a bimetallic valve that operates according to the temperature of the refrigerant sucked into the guide vane.

[0074] According to such a configuration, the bimetallic valve is configured to operate according to the temperature of the refrigerant sucked into the guide vane, and can be configured into various valve structures together with the above-mentioned differential pressure valve as needed.

[0075] (30) In any one of the above (16) to (29), the impeller includes: a first impeller rotatably coupled to one end of the rotating shaft; and a second impeller rotatably coupled to the other end of the rotating shaft; the guide vane includes: a first guide vane compressing the working fluid sucked in through the first impeller; and a second guide vane further compressing the compressed working fluid sucked in from the first guide vane through the second impeller; one side of the bypass flow path can be connected to the first guide vane, and the other side of the bypass flow path can be connected to the interior of the cover body.

[0076] Thereby, when the rotating shaft operates abnormally, it is possible to actively cope with the phenomenon in which the axial load of the rotating shaft is biased, that is, biased from the second impeller to the first impeller.

[0077] Effects of the Invention

[0078] According to the embodiments of the present invention, the following effects can be achieved.

[0079] First, the radial bearing includes an air foil bearing installed on the inner circumference of the bearing cover to separate the air gap from the rotating shaft and support the radial load of the rotating shaft. The radial bearing safety device is arranged on the inner circumference of the bearing cover. The radial bearing safety device limits the radial movable range of the rotating shaft to the elastic deformation range of the radial bearing. As an embodiment, a limiter is formed to protrude from the inner circumference of the bearing cover toward the rotating shaft. The limiter can contact the rotating shaft to limit the radial movement of the rotating shaft. Therefore, the limiter limits the radial movement distance of the rotating shaft, so that when the radial bearing supports the radial load of the rotating shaft, even if the rotating shaft moves abnormally due to abnormal operation caused by external impact or liquid refrigerant, etc., the radial bearing can be prevented from plastic deformation.

[0080] Second, the stopper protrudes from the inner peripheral surface of the bearing cover and is formed integrally, so there is no need to assemble additional components for preventing the radial bearing from being damaged. Therefore, the number of components and the number of assembly steps can be reduced, and it also greatly contributes to reducing manufacturing costs.

[0081] Third, the stopper is formed into a structure protruding from the inner peripheral surface of the bearing cover body, so the durability can be improved by simplifying the structure.

[0082] Fourth, the protruding height of the stopper protruding from the inner circumferential surface of the bearing cover is lower than the wave height from the inner circumferential surface of the bearing cover to the vertex of the curved surface of the air foil bearing in the radial direction, and the protruding height of the stopper is higher than the height of the wave anti-slip ring protruding from the annular groove toward the rotating shaft, based on the inner circumferential surface of the bearing cover. Therefore, when the rotating shaft moves abnormally, the radial movement of the rotating shaft is stopped by the stopper before the rotating shaft contacts the wave anti-slip ring, thereby preventing the rotating shaft from being damaged due to the contact between the rotating shaft and the wave anti-slip ring.

[0083] Fifth, as another embodiment of the radial bearing safety device, a stop ring, a ball bearing and a needle bearing can be used. A groove is formed on the inner circumference of the bearing cover body for the stop ring, the ball bearing and the needle bearing to be combined. The groove can be arranged adjacent to the front end or the rear end of the inner circumference of the bearing cover body, so that the stop ring, the ball bearing and the needle bearing are easy to assemble into the groove, or easy to disassemble from the groove.

[0084] Sixth, the ball bearing and the needle bearing are arranged in a circumferential direction along the inner circumferential surface of the bearing cover. Therefore, compared with the stop ring extending in the circumferential direction along the inner circumferential surface of the bearing cover, the contact area between the ball bearing and the needle bearing and the rotating shaft is reduced. Therefore, when the rotating shaft moves abnormally due to external impact, the ball bearing or the needle bearing is in point contact or line contact with the rotating shaft, and the contact area is reduced, so that the radial bearing and the rotating shaft can be minimized.

[0085] Seventh, the limiting portion, the limiting ring, the ball bearing, and the needle bearing have surfaces formed with a wear-resistant coating, thereby minimizing damage to the radial bearing and the rotating shaft caused by contact with the rotating shaft.

[0086] Eighth, the limiting portion, the limiting ring, the ball bearing and the needle bearing limit the radial movement range of the rotating shaft within the elastic deformation range of the radial bearing, thereby having the advantage of easy alignment between the radial bearing and the rotating shaft.

[0087] Ninth, a bypass flow path is formed to connect the guide vanes of the impeller housing and the inside of the cover so that communication is possible. The bypass flow path bypasses a part of the high-pressure refrigerant or liquid refrigerant flowing toward the compression part (guide vanes) and transmits it to the inside of the cover.

[0088] As a result, pressure balance is achieved between the guide vane and the cover body, so that the difference between the axial pressure on the first impeller side and the axial pressure on the second impeller side can be minimized.

[0089] Tenth, a part of the bypassed refrigerant forms an oil film between the thrust bearing and the thrust mirror plate. Thus, the bypassed refrigerant plays a role in lubricating the thrust bearing, thereby preventing the thrust bearing from being damaged by the axial load applied to the rotating shaft.

[0090] Eleventh, when the liquid refrigerant flows into the guide vane, the bypass flow path bypasses a portion of the liquid refrigerant to flow into the inside of the cover, thereby minimizing the inflow of the liquid refrigerant into the compression portion (guide vane).

[0091] Twelfth, the bypass flow path and the on-off valve that opens and closes it are arranged on the inner side of the guide vane or the bearing cover, which not only reduces the number of parts but also contributes to miniaturization and reduces manufacturing costs.

[0092] Thirteenth, the on-off valve operates by a mechanical mechanism in which the rotating shaft contacts the thrust mirror plate due to the axial movement of the rotating shaft, so that the structure is simple and the installation space can be minimized.

[0093] Fourteenth, as a structure in which only the on-off valve and the valve connecting rod are additionally installed and assembled to the inner side of the bearing cover body, there is an advantage of easy assembly and disassembly.

[0094] Fifteenth, the bypassed refrigerant moves in a direction opposite to the axial movement direction of the rotating shaft, thereby being able to offset the axial force. This has the advantage of being easy to align the bearing and the rotating shaft without requiring additional components. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Figure 1 This is a conceptual diagram showing an example of a turbo compressor according to the present invention.

[0096] Figure 2 Yes Figure 1 An enlarged partial view of part II in FIG.

[0097] Figure 3 It shows the axial direction Figure 2 Conceptual diagram of the situation of radial bearings in .

[0098] Figure 4 It is shown Figure 3 An exploded perspective view of the radial bearing in FIG.

[0099] Figure 5 is along Figure 4 The cross-sectional view taken along the line VV in FIG. 1 is a conceptual diagram for explaining a radial bearing safety device 1 according to an embodiment of the present invention.

[0100] Figure 6 This is a conceptual diagram of a radial bearing safety device 2 according to another embodiment of the present invention installed on a first bearing cover body, viewed along the axial direction.

[0101] Figure 7 is along Figure 6 A cross-sectional view taken along line VII-VII.

[0102] Figure 8 Yes Figure 7 An enlarged view of part VIII is shown.

[0103] Fig. 9 This is a conceptual diagram of a radial bearing safety device 3 according to another embodiment of the present invention installed on a first bearing cover, viewed along the axial direction.

[0104] Fig.10 Yes Fig. 9 The X portion is enlarged to show the enlarged view.

[0105] Fig.11 This is a conceptual diagram of a radial bearing safety device 4 according to another embodiment of the present invention installed on a first bearing cover as viewed along the axial direction.

[0106] Fig.12 Yes Fig.11 An enlarged view of the part XII is shown.

[0107] Fig.13 This is a conceptual diagram for explaining the structure of a turbo compressor according to another embodiment of the present invention.

[0108] Fig.14 It shows the axial direction Fig.13 Conceptual diagram of the situation of a thrust bearing in FIG.

[0109] Fig.15 is along Fig.14 A cross-sectional view taken along the XV-XV line (circumferential curve).

[0110] Fig.16 Yes Fig.13 A conceptual diagram of the thrust bearing safety device 1 is shown with part XVI enlarged.

[0111] Fig.17 It is shown Fig.16 A conceptual diagram of a situation in which an embodiment of the thrust bearing safety device 1 is more specifically implemented.

[0112] Fig.18 It is shown Fig.17 A sectional view of the thrust bearing safety device 1 before operation.

[0113] Fig.19 It is used to illustrate Fig.16 Schematic diagram of the thrust bearing safety device 1 after operation.

[0114] Fig. 20 It specifically shows Fig.19 Schematic diagram of the thrust bearing safety device 1 after operation.

[0115] Fig.21 It specifically shows Fig. 20A cross-sectional view of the thrust bearing safety device 1 after operation.

[0116] Fig. 22 is along Fig.21 A conceptual diagram showing the connection state between the opening and closing valve and the hinge pin, with the XXII-XXII line in FIG.

[0117] Fig.23 This is a conceptual diagram for explaining a situation before a thrust bearing safety device 2 according to another embodiment of the present invention is operated.

[0118] Fig.24 It is used to illustrate Fig.23 A conceptual diagram of the thrust bearing safety device 2 after operation.

[0119] Fig.25 This is a conceptual diagram for explaining a thrust bearing safety device 3 according to still another embodiment of the present invention.

[0120] Fig.26 Yes Fig.25 Part XXVI in FIG. 1 is enlarged to illustrate a conceptual diagram of the working state of the thrust bearing safety device 3 .

[0121] Fig. 27 This is a conceptual diagram for explaining a thrust bearing safety device 4 according to still another embodiment of the present invention.

[0122] Fig.28 Yes Fig. 27 Part XXVIII in FIG. 1 is enlarged to illustrate a conceptual diagram of the working state of the thrust bearing safety device 4.

[0123] Fig.29 This is a conceptual diagram for explaining a thrust bearing safety device 5 according to still another embodiment of the present invention. DETAILED DESCRIPTION

[0124] Hereinafter, a turbo compressor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0125] In the following description, in order to make the features of the present invention more clear, the description of some components may be omitted.

[0126] 1. Definition of terms

[0127] When it is mentioned that a certain component is “connected” or “linked” to another component, it should be understood that it may be directly connected or linked to the other component, but other components may be present between them.

[0128] On the contrary, if it is mentioned that a certain component is “directly connected to” or “directly linked to” another component, it should be understood that there are no other components between them.

[0129] Unless the context clearly indicates otherwise, an expression in the singular used in this specification includes an expression in the plural.

[0130] The "axial direction" used in the following description refers to the axial direction of the rotation shaft.

[0131] The "radial direction" used in the following description refers to the radial direction of the rotation axis.

[0132] 2. Description of the structure of a turbo compressor according to an embodiment of the present invention

[0133] Hereinafter, various components of a turbo compressor according to an embodiment of the present invention will be described with reference to the drawings.

[0134] Figure 1 This is a conceptual diagram showing an example of a turbo compressor according to the present invention.

[0135] Figure 2 Yes Figure 1 An enlarged partial view of part II in FIG.

[0136] Figure 3 It shows the axial direction Figure 2 A conceptual diagram of the radial bearing 124 in FIG.

[0137] Figure 4 It is shown Figure 3 1 is an exploded perspective view of a radial bearing 124 in the exploded state.

[0138] The turbo compressor of the present invention includes a housing 100 , an electric unit 120 , a rotating shaft 119 , an impeller 123 , an impeller housing 110 , a bearing housing 128 , a thrust bearing 127 , and a radial bearing 124 .

[0139] (1) Compressor components

[0140] The cover body 100 may be formed in a cylindrical shape and may form the appearance of the turbo compressor.

[0141] Both sides of the cover 100 may be fastened to the impeller housing 110 .

[0142] An accommodation space is formed inside the housing 100. The accommodation space of the housing 100 may be divided into a first space 117 and a second space 118. The first space 117 and the second space 118 may be divided by a partition wall 116.

[0143] The partition wall 116 may be formed to protrude radially from the inner circumferential surface of the housing 100 toward the rotation axis 119. The partition wall 116 may extend in a circumferential direction along the inner circumferential surface of the housing 100. The partition wall 116 may be formed in a disc shape having a predetermined thickness.

[0144] A shaft through hole may be formed in a central portion of the partition wall 116 so that the rotating shaft 119 can pass therethrough.

[0145] The partition wall 116 and the rotating shaft 119 are arranged to be spaced apart from each other at a predetermined interval in the radial direction.

[0146] The partition wall 116 may be disposed offset from the center of the cover body 100 in the longitudinal direction in one direction.

[0147] The first space 117 may be open to one side of the housing 100 , and the second space 118 may be open to the other side of the housing 100 .

[0148] The volumes of the first space 117 and the second space 118 may be different from each other. The volume of the first space 117 may be smaller than the volume of the second space 118.

[0149] The electric unit 120 described later may be accommodated in the second space 118 having a relatively large volume. A portion of the first bearing cover 1281 described later may be accommodated in the first space 117. The second bearing cover 1282 described later may be accommodated in the second space 118.

[0150] The rotating shaft 119 may be horizontally disposed in the first space 117 and the second space 118 to axially cross a radial center portion of the housing 100 .

[0151] The electric part 120 includes a stator 121 and a rotor 122. The stator 121 has a stator core 1211 and a stator coil 1212. The stator core 1211 may be formed in a cylindrical shape by stacking and combining a plurality of electrical steel sheets.

[0152] The stator core 1211 may be formed such that a plurality of teeth protrude radially toward the rotating shaft 119 at the inner side of the stator core 1211. A plurality of slits may be formed between the plurality of teeth. The plurality of teeth and the plurality of slits may be alternately arranged along the circumferential direction of the stator core 1211 and spaced apart in the circumferential direction.

[0153] The stator coil 1212 is wound around the stator core 1211 through the slits.

[0154] When power is applied to the stator coil 1212 , a magnetic field is generated around the stator coil 1212 .

[0155] The rotor 122 is arranged inside the stator 121. The rotor 122 is arranged with an air gap between it and the stator 121. The rotor 122 is attached to the rotating shaft 119 so as to be rotatable relative to the stator 121.

[0156] The rotor 122 may include a rotor core and a permanent magnet 1221. The rotor core may be installed to be rotatable together with the rotating shaft 119 or may be omitted. In the case where the rotor core is omitted, the permanent magnet 1221 may be installed to the rotating shaft 119.

[0157] The permanent magnet 1221 may be disposed on the rotating shaft 119 or the rotor core so as to be spaced apart from an air gap and overlapped in the radial direction with the inner side surface of the stator 121. In this embodiment, the case where the permanent magnet 1221 is mounted on the rotating shaft 119 is shown.

[0158] A rotor support portion may be provided on the rotating shaft 119. The rotor support portion may be arranged at the center along the axial direction of the rotating shaft 119. The rotor support portion may be formed to be recessed or protruded in the radial direction of the rotating shaft 119.

[0159] The permanent magnet 1221 can be installed to be accommodated in the rotor support part, or can be fixed between multiple rotor support parts so that the axial movement is limited by the protruding rotor support part. In this embodiment, the rotor support part is formed to protrude radially from the rotating shaft 119, and the permanent magnet 1221 is arranged and fixed between multiple rotor support parts.

[0160] The permanent magnet 1221 is formed in a ring shape. The inner diameter of the permanent magnet 1221 may have the same diameter as the diameter of the rotating shaft 119. The outer diameter of the permanent magnet 1221 may be formed to be smaller than the inner diameter of the stator 121 core.

[0161] According to such a configuration, when power is applied to the stator 121 , the rotor 122 may rotate relative to the stator 121 due to electromagnetic interaction between the stator 121 and the rotor 122 .

[0162] The rotating shaft 119 is configured to rotate together with the rotor 122 and transmit a rotational force to an impeller 123 described later.

[0163] Both ends of the rotating shaft 119 may be supported by bearings. The bearings include a first bearing and a second bearing.

[0164] The first bearing supports one side of the rotating shaft 119. The first bearing may be disposed between the electric unit 120 and a primary impeller 123 described later.

[0165] The second bearing supports the other side of the rotating shaft 119. The second bearing may be disposed between the electric unit 120 and a secondary impeller 123 described later.

[0166] The bearing may include a radial bearing 124 supporting a radial load of the rotating shaft 119 and a thrust bearing 127 supporting an axial load of the rotating shaft 119 .

[0167] The first bearing may include a first radial bearing 1241 , a first thrust bearing 1271 , and a second thrust bearing 1272 .

[0168] The second bearing may include a second radial bearing 1242 .

[0169] The bearing cover 128 includes a first bearing cover 1281 and a second bearing cover 1282 .

[0170] The first bearing cover 1281 supports the first bearing. It should be noted that the second thrust bearing 1272 may be supported by the partition wall 116 .

[0171] The first bearing cover 1281 may be formed in a cylindrical shape. The first bearing cover 1281 may have a circular groove portion formed radially inward.

[0172] The first bearing cover 1281 may be disposed between the first impeller housing 111 and the partition wall 116 of the housing 100. A portion of the first bearing cover 1281 may be accommodated in the first space 117 of the housing 100, and another portion of the first bearing cover 1281 may be accommodated inside the first impeller housing 111.

[0173] The first bearing cover 1281 may be press-fitted and coupled to the inner sides of the first impeller housing 111 and the cover 100 .

[0174] A first shaft hole is formed inside the first bearing cover 1281 so that the rotating shaft 119 passes therethrough. The first shaft hole is formed to be larger than the diameter of the rotating shaft 119.

[0175] The first bearing may be mounted on the first bearing cover 1281 .

[0176] The first radial bearing 1241 may be installed to be accommodated radially inside the first bearing housing 1281 .

[0177] The first thrust bearing 1271 may be mounted on the axial back side of the first bearing cover 1281 .

[0178] The rotation shaft 119 is provided with a thrust mirror plate 129. The thrust mirror plate 129 may be formed to protrude from the rotation shaft 119 toward the first space 117 in a radial direction. The thrust mirror plate 129 may rotate together with the rotation shaft 119.

[0179] The first thrust bearing 1271 may be spaced apart from an axial side surface of the thrust mirror plate 129 in the axial direction.

[0180] The second thrust bearing 1272 may be mounted on the partition wall 116. The second thrust bearing 1272 may be disposed on the opposite side of the first thrust bearing 1271 with the thrust mirror plate 129 interposed therebetween.

[0181] The second thrust bearing 1272 may be spaced apart from the other axial side surface of the thrust mirror plate 129 in the axial direction.

[0182] The second bearing cage 1282 may include a bearing receiving portion and a radially extending portion.

[0183] A cylindrical second shaft hole is provided inside the bearing accommodation portion. The rotating shaft 119 passes through the second shaft hole in the axial direction. The outer peripheral surface of the bearing accommodation portion may be formed to be inclined relative to the axial direction.

[0184] The second radial bearing 1242 may be installed on the inner side of the bearing receiving portion. The second radial bearing 1242 is spaced apart from the rotating shaft 119 with a gap in the radial direction.

[0185] The radially extending portion may protrude and extend from the outer circumference of the bearing accommodation portion toward the radial outside. The radially extending portion may extend along the circumferential direction in a disc shape.

[0186] The radially extending portion may be coupled to the inner side of the other end portion of the cover body 100 .

[0187] The bearing accommodation portion may protrude from the radially extending portion toward the second space 118 of the cover body 100 in the axial direction.

[0188] According to such a configuration, the first radial bearing 1241 and the second radial bearing 1242 can support the radial load of the rotating shaft 119 .

[0189] The first thrust bearing 1271 and the second thrust bearing 1272 can support the axial load of the rotating shaft 119 via the thrust mirror plate 129 .

[0190] The radial bearing 124 and the thrust bearing 127 of this embodiment can be respectively implemented by air foil bearings.

[0191] The air foil bearing supports the rotating shaft 119 using working fluid.

[0192] The working fluid may be a refrigerant or air, etc. The air foil bearing may be arranged to be spaced apart from the rotating shaft 119 by a predetermined interval (air gap).

[0193] The air foil bearing can rotatably support the rotating shaft 119 using the force of the working fluid filling the gap between the rotating shaft 119 and the bearing.

[0194] The bearing of the present invention is configured to be separated from the rotating shaft 119, and can support the rotating shaft 119 in a non-contact manner so that it can rotate. Accordingly, as the rotating shaft 119 rotates at high speed, an air gap is stably formed between the rotating shaft 119 and the bearing, and the center of the rotating shaft 119 is located at the center of the bearing. When the rotation speed is further increased, under the action of centrifugal force, the pressure of the air gap rises and the shaft supporting force increases, thereby realizing a frictionless and efficient compressor. In addition, the noise is small and the wear is reduced, so that the life of the bearing can be extended. In addition, the bearing of the present invention does not require lubricating oil, so there is no need to replace the lubricating oil, and no maintenance and management costs are incurred.

[0195] The air foil bearing may be made of an elastic material. The air foil bearing comprises a bump foil 125 and a cover foil 126 .

[0196] The bump foil 125 is formed in an embossed form and has elasticity. The cover foil 126 is arranged to cover the bump foil 125 .

[0197] The bump foil 125 includes a curved portion 1251 and a connecting portion 1252. The curved portion 1251 may be formed in a semicircular shape. A plurality of the curved portion 1251 and the connecting portion 1252 may be provided.

[0198] When the radial bearing 124 is implemented by an air foil bearing, the bump foil 125 may be formed into a structure in which a thin steel plate is rolled into a cylindrical shape.

[0199] The plurality of curved surface portions 1251 and connecting portions 1252 are alternately arranged along the circumferential direction.

[0200] The curved surface portion 1251 may be disposed facing the outer peripheral surface of the rotating shaft 119. The curved surface portion 1251 may be formed to protrude toward the rotating shaft 119.

[0201] The connection portion 1252 connects the curved surface portions 1251 adjacent to each other in the circumferential direction.

[0202] The connection portion 1252 may be configured to be in contact with the inner circumferential surface of the bearing cover 128. The connection portion 1252 may extend along the inner circumferential surface of the bearing cover 128 in the circumferential direction.

[0203] The bump foil 125 includes a bump fixing portion 1253. The bump fixing portion 1253 is provided at one end of the bump foil 125. The other end of the bump foil 125 curled into a cylindrical shape and the bump fixing portion 1253 may be disposed adjacent to each other.

[0204] The wave fixing portion 1253 may be bent radially outward from the connecting portion 1252 .

[0205] A fixing groove 1283 for fixing the bump foil 125 may be formed on the inner circumferential surface of the bearing cover 128. The bump fixing portion 1253 may be inserted and coupled to the fixing groove 1283.

[0206] The cover foil 126 includes a cover fixing portion 1261. The cover foil 126 may be formed into a structure in which a thin steel plate is rolled into a cylindrical shape so that both ends are arranged adjacent to each other. The cover fixing portion 1261 is provided at the other end of the cover foil 126 rolled into a cylindrical shape.

[0207] The cover fixing portion 1261 is disposed facing the wave fixing portion 1253. The cover fixing portion 1261 is inserted into and coupled to the fixing groove 1283 so that the cover foil 126 is fixed to the bearing cover 128.

[0208] The bump foil 125 is disposed so as to surround the cover foil 126. The cover foil 126 may extend in the circumferential direction so as to contact the top of the curved surface portion 1251 that is formed to protrude toward the rotation shaft 119 in a semicircular shape.

[0209] The rotating shaft 119 can move in the radial direction to contact the cover foil 126. The cover foil 126 transmits the force received from the rotating shaft 119 to the bump foil 125. The bump foil 125 can be deformed within an elastic range under the effect of the force transmitted through the cover foil 126.

[0210] When the bump fixing portion 1253 and the cover fixing portion 1261 are fixed inside the fixing groove 1283, a surplus space may be formed between the cover fixing portion 1261 and the other end of the bump foil 125 so that the bump foil 125 and the cover foil 126 can be elastically deformed. In addition, a surplus space may also be formed between the cover fixing portion 1261 and one end of the cover foil 126.

[0211] The turbo compressor can compress the refrigerant in multiple stages according to the number of impellers 123. In this embodiment, a case where it is configured as a two-stage compressor is shown.

[0212] The impeller 123 can be divided into the first impeller 1231 to the Nth impeller according to the compression order of the refrigerant. In this embodiment, the impeller 123 is composed of the first impeller 1231 and the second impeller 1232. The first impeller 1231 can be called a primary impeller 123, and the second impeller 1232 can be called a secondary impeller 123.

[0213] In the present specification, the description of the structure of the impeller 123 can also be applied to the first impeller 1231 and the second impeller 1232 without separately distinguishing between the first impeller 1231 and the second impeller 1232 .

[0214] The fluid such as the refrigerant and / or air can be compressed in the first impeller 1231 and then compressed in the second impeller 1232 (recompressed).

[0215] The impeller 123 is mounted on the rotating shaft 119 so as to be rotatable together with the rotating shaft 119. The impeller 123 can receive power from the electric unit 120 through the rotating shaft 119 to rotate.

[0216] The impeller 123 sucks a fluid such as a refrigerant to compress the fluid such as the refrigerant while rotating with the rotating shaft 119 .

[0217] A first impeller support portion and a second impeller support portion may be provided at both ends of the rotating shaft 119 .

[0218] The first impeller support portion has a diameter smaller than that of the rotating shaft 119 and may be formed to protrude in the axial direction from one end of the rotating shaft 119. The first impeller support portion may be press-fitted into the inner side of the hub 123a coupled to the first impeller 1231.

[0219] The second impeller support portion has a diameter smaller than that of the rotating shaft 119 and may be formed to protrude in the axial direction from the other end of the rotating shaft 119. The second impeller support portion may be press-fitted into the inner side of the hub 123a coupled to the second impeller 1232.

[0220] The impeller 123 includes a hub 123a and a plurality of blades 123b.

[0221] A through hole is provided inside the hub 123a so that the rotating shaft 119 passes through. The hub 123a may be formed in a conical shape. The outer peripheral surface of the hub 123a may be formed to be inclined relative to the axial direction. As the axial side of the hub 123a approaches the axial other side of the hub 123a, the diameter of the hub 123a may gradually increase.

[0222] The plurality of blades 123b may be formed to protrude in a spiral shape on the outer peripheral surface of the hub 123a. The plurality of blades 123b may be spaced apart in the circumferential direction of the hub 123a.

[0223] According to such a configuration, the impeller 123 can suck in a gas such as a refrigerant in the axial direction and discharge the sucked gas in a centrifugal direction of the impeller 123 .

[0224] The first impeller housing 111 is fastened to one side of the housing 100. The axial back side of the first impeller housing 111 may be covered by a first bearing housing 1281 accommodated in one side of the housing 100.

[0225] The second impeller housing 112 is fastened to the other side of the housing 100. The axial back side of the second impeller housing 112 may be covered by a second bearing housing 1282 accommodated at the other side of the housing 100. The axial back sides of the first impeller housing 111 and the second impeller housing 112 refer to the downstream side of the impeller housing 110 based on the flow direction of the refrigerant.

[0226] The first impeller casing 111 includes suction ports 113 a and 113 b , guide vanes 114 a and 114 b , and discharge ports 115 a and 115 b .

[0227] The suction ports 113a and 113b are formed axially through the center of the first impeller housing 111. One side of the suction ports 113a and 113b can communicate with the outside of the first impeller housing 111, and the other side of the suction ports 113a and 113b can communicate with the inside of the first impeller housing 111.

[0228] The first impeller 1231 is accommodated inside the suction ports 113a and 113b. The first impeller 1231 may be mounted on the first impeller support portion to rotate together with the rotation shaft 119.

[0229] The suction ports 113a and 113b may be formed so that the diameter thereof decreases as it approaches the other side in the axial direction from the one side in the axial direction. Thus, the flow rate of the refrigerant sucked through the suction ports 113a and 113b may be increased.

[0230] The guide vanes 114a and 114b are formed to be recessed in the axial direction on the axial back side of the first impeller housing 111. The guide vanes 114a and 114b are formed inside the first impeller housing 111. The guide vanes 114a and 114b are arranged between the suction ports 113a and 113b and the discharge ports 115a and 115b.

[0231] The guide vanes 114a and 114b may be formed to extend from the suction ports 113a and 113b in a spiral direction. The guide vanes 114a and 114b are connected to the suction ports 113a and 113b and the discharge ports 115a and 115b so as to communicate with each other. The guide vanes 114a and 114b are formed so that the size of the flow path increases as the suction ports 113a and 113b approach the discharge ports 115a and 115b.

[0232] According to such a configuration, as the size of the flow path of the guide vanes 114a and 114b increases, the working fluid sucked in by the rotation of the impeller 123 increases in pressure while passing through the guide vanes 114a and 114b.

[0233] That is, the guide vanes 114a and 114b can increase the pressure of the refrigerant by converting the kinetic energy of the refrigerant sucked through the suction ports 113a and 113b into pressure energy.

[0234] The discharge ports 115a and 115b are provided at the outer peripheral portion of the first impeller housing 111. The discharge ports 115a and 115b may extend radially from the guide vanes 114a and 114b. The discharge pipe may be formed to protrude outward from the outer peripheral portion of the first impeller housing 111.

[0235] One side of the discharge pipe may be communicated with the discharge ports 115 a and 115 b , and the other side of the discharge pipe may be communicated with the outside of the first impeller housing 111 .

[0236] The second impeller housing 112 includes suction ports 113a, 113b, guide vanes 114a, 114b, and discharge ports 115a, 115b. The suction ports 113a, 113b, guide vanes 114a, 114b, and discharge ports 115a, 115b of the second impeller housing 112 are the same as or similar to the suction ports 113a, 113b, guide vanes 114a, 114b, and discharge ports 115a, 115b of the first impeller 1231, and therefore, repeated descriptions are omitted.

[0237] It should be noted that, in order to perform two-stage compression, the discharge pipe of the first impeller casing 111 and the suction ports 113 a and 113 b of the second impeller casing 112 may be connected via a connecting pipe (not shown).

[0238] The first impeller housing 111 and the second impeller housing 112 may each be separably formed of two parts.

[0239] One part is a suction part 111a, 112a. The suction part 111a, 112a may be formed to have a T-shaped cross-sectional shape. The suction part 111a, 112a may be composed of a radial part extending in the radial direction and an axial part extending in the axial direction. The suction ports 113a, 113b are formed on the inner side of the axial part of the suction part 111a, 112a.

[0240] The downstream side portion of the suction portion 111 a , 112 a may be formed in a curved surface form of an arc shape. The downstream side portion of the suction portion 111 a , 112 a accommodates the impeller 123 .

[0241] The other part is the guide vane portion 111b, 112b. The guide vane portion 111b, 112b surrounds the outer circumference and back surface of the radial portion of the suction portion 111a, 112a and the outer circumference of the axial portion. The suction portion 111a, 112a and the guide vane portion 111b, 112b are combined with each other.

[0242] The back surface of the radial portion of the suction portion 111 a , 112 a refers to a downstream side surface based on the refrigerant suction direction.

[0243] In order to prevent refrigerant leakage, radial sealing members and axial sealing members are provided.

[0244] The radial sealing member may be disposed between the bearing housing 128 and the impeller 123. In this embodiment, a radial sealing member is disposed between the first bearing housing 1281 and the impeller 123.

[0245] The radial sealing member may be composed of a first radial sealing portion 130 and a second radial sealing portion 134 .

[0246] For example, a first radial sealing portion 130 may be provided on an axial side surface of the first bearing cover body 1281 .

[0247] The first radial sealing portion 130 may be integrally formed on an axial side surface of the first bearing cover body 1281 , or may be combined with an axial side surface of the first bearing cover body 1281 .

[0248] In this embodiment, the first radial seal 130 is combined with an axial side surface of the first bearing housing 1281. To this end, a seal receiving groove 131 may be formed on an axial side surface of the first bearing housing 1281 to receive the first radial seal 130.

[0249] The first radial sealing portion 130 includes a plurality of sealed grooves 132 and a plurality of first base portions 133 .

[0250] The plurality of sealed grooves 132 may be formed by being recessed in the axial direction on one axial side (front side) of the first radial sealing portion 130 in the opposite direction of the impeller 123. The plurality of sealed grooves 132 may extend in the circumferential direction of the first radial sealing portion 130.

[0251] The front side of the first radial seal portion 130 refers to a side facing the impeller 123 .

[0252] The plurality of sealed grooves 132 may be arranged spaced apart in the radial direction of the first radial sealing portion 130 .

[0253] The plurality of sealed grooves 132 may be arranged to overlap with the impeller 123 along the axial direction.

[0254] The plurality of first base portions 133 may be disposed between the plurality of sealed grooves 132 .

[0255] The plurality of sealed grooves 132 and the plurality of first base portions 133 may be alternately arranged along the radial direction of the first radial sealing portion 130 .

[0256] The plurality of sealed grooves 132 and the plurality of first base portions 133 may be formed in a ring shape, respectively. However, the radial width of the sealed groove 132 and the radial thickness of the first base portion 133 may be formed to be different from each other.

[0257] A second radial seal portion 134 may be provided on the other axial side (back side) of the first impeller 1231. The back side of the first impeller 1231 is a side facing the first radial seal portion 130.

[0258] The second radial seal portion 134 is disposed on the downstream side of the first impeller 1231 based on the flow direction of the refrigerant. The second radial seal portion 134 can rotate together with the first impeller 1231.

[0259] The second radial sealing portion 134 includes a plurality of sealing protrusions 135 .

[0260] A plurality of sealing protrusions 135 are formed to protrude axially from the other axial side surface of the hub 123a of the first impeller 1231 toward the first radial sealing portion 130. The plurality of sealing protrusions 135 can be respectively received in the plurality of sealing grooves 132.

[0261] The sealing protrusion 135 is received in the sealing groove 132 and is spaced apart from the inner side surface of the sealing groove 132 at a predetermined interval in the axial direction and the radial direction.

[0262] The sealing protrusion 135 extends in the circumferential direction of the hub 123 a and may be formed in a ring shape.

[0263] The plurality of sealing protrusions 135 and the plurality of first base portions 133 may be overlapped in the radial direction.

[0264] According to such a configuration, by arranging the plurality of sealing protrusions 135 and the plurality of first base portions 133 to overlap in the radial direction, it is possible to prevent the refrigerant discharged from the impeller 123 from leaking to the guide vanes 114 a and 114 b .

[0265] For example, when the impeller 123 rotates, the plurality of blades 123 b rotate around the hub 123 a , so that the impeller 123 can discharge the refrigerant sucked through the spaces between the plurality of blades 123 b in the radial direction toward the guide vanes 114 a and 114 b .

[0266] Here, the multiple sealed protrusions 135 and the first base portion 133 act as flow resistance for the refrigerant flowing from the guide vanes 114a, 114b toward the downstream side of the impeller 123, thereby preventing the refrigerant from flowing radially inward through the gap between the sealed groove 132 of the first radial sealing portion 130 and the back side of the impeller 123.

[0267] In addition, the above-mentioned radial sealing component can also be similarly applied between the second bearing cover 1282 and the second impeller 1232.

[0268] The axial sealing member may be disposed between the second bearing housing 1282 and the second impeller housing 112. The axial sealing member may be composed of a first axial sealing portion 136 and a second axial sealing portion.

[0269] The first axial seal portion 136 may be disposed inside the guide vane portions 111b, 112b of the second impeller housing 112. The first axial seal portion 136 may be coupled between the second bearing cover 1282 and the guide vane portions 111b, 112b of the second impeller housing 112.

[0270] The first axial sealing portion 136 includes a plurality of sealing grooves. The plurality of sealing grooves may be recessed in the radial direction from the inner side surface of the first axial sealing portion 136, more specifically, from the inner side surface of the bearing accommodation portion.

[0271] The sealing groove may be formed in a ring shape and may extend in the circumferential direction along the inner peripheral edge of the first axial sealing portion 136 .

[0272] The plurality of sealing grooves may be arranged axially spaced apart on the inner side of the first axial sealing portion 136. A second base portion may be arranged between the plurality of sealing grooves. The plurality of sealing grooves and the plurality of second base portions may be arranged axially alternately spaced apart on the inner side surface of the first axial sealing portion 136.

[0273] The second axial sealing portion may be disposed on the other side of the rotating shaft 119. The second axial sealing portion may rotate together with the first impeller 1231. The second axial sealing portion may overlap with the sealing groove in the radial direction to be accommodated in the sealing groove.

[0274] The second axial sealing portion includes a plurality of sealing protrusions.

[0275] The plurality of sealing protrusions may be formed to protrude radially outward from the outer circumferential surface of the rotating shaft 119 toward the inner side surface of the sealing groove. The plurality of sealing protrusions may be formed in a ring shape.

[0276] The plurality of sealing protrusions are arranged on the rotating shaft 119 at intervals in the axial direction.

[0277] The plurality of sealing protrusions and the plurality of second base portions may be alternately arranged along the axial direction of the rotating shaft 119. The plurality of sealing protrusions and the plurality of second base portions are arranged to be spaced apart from each other at predetermined intervals along the axial direction.

[0278] The plurality of second base portions are spaced apart from the rotation shaft 119 at predetermined intervals in the radial direction.

[0279] The plurality of sealing protrusions are arranged radially apart from the inner side surface of the first axial sealing portion 136 at predetermined intervals.

[0280] The plurality of sealing protrusions and the second base portion are arranged to overlap in the axial direction.

[0281] According to such a configuration, by arranging the plurality of sealing protrusions and the second base portion to overlap in the axial direction, leakage of a fluid such as a refrigerant sucked in by the second impeller 1232 can be prevented.

[0282] For example, when the second impeller 1232 rotates, the plurality of blades 123 b rotate around the hub 123 a , so that the second impeller 1232 can draw refrigerant in the axial direction through the spaces between the plurality of blades 123 b .

[0283] Here, the plurality of sealing protrusions and the second base portion act as flow resistance for the refrigerant flowing through the gap between the first axial sealing portion 136 and the rotating shaft 119 , thereby preventing the refrigerant from leaking through the gap between the inner surface of the first axial sealing portion 136 and the rotating shaft 119 .

[0284] The above-mentioned axial sealing member may also be similarly applied between the first bearing cover 1281 and one side of the rotating shaft 119 .

[0285] (2) Radial bearing safety device 1

[0286] Figure 5 is along Figure 4 The cross-sectional view taken along the line VV in FIG. 1 is a conceptual diagram for explaining a radial bearing safety device 1 according to an embodiment of the present invention.

[0287] The present invention can respond to abnormal operation caused by external impact, liquid refrigerant, etc.

[0288] The bump foil 125 of the radial bearing 124 can support the radial load by using spring characteristics. However, if an impact exceeding a predetermined level is applied, the bump foil 125 will be plastically deformed.

[0289] The turbo compressor of the present invention includes a radial bearing safety device having a structure capable of minimizing plastic deformation of the radial bearing 124 and preventing damage to the rotating shaft 119 .

[0290] In this embodiment, a case where the radial bearing 124 is implemented by an air foil bearing is shown.

[0291] The radial bearing 124 may include a bump foil 125 , a cover foil 126 , a bump anti-slip ring 141 and a stopper 143 .

[0292] The configurations of the bump foil 125 and the cover foil 126 are replaced by those described above.

[0293] The wave-proof ring 141 may be formed in a ring shape with one side open. The wave-proof ring 141 includes a ring body 1411 and an inner hole 1412. The ring body 1411 forms the appearance of the wave-proof ring 141.

[0294] The ring body 1411 is formed in a circular ring shape. One side of the ring body 1411 is opened in a radial direction. The ring body 1411 may have a circular cross-sectional shape.

[0295] A circular inner hole 1412 is formed inside the ring body 1411 . The diameter of the inner hole 1412 is larger than the diameter of the rotating shaft 119 .

[0296] The wave prevention ring 141 is formed in a C-shape, so it can be called a C-ring.

[0297] The wave anti-detachment ring 141 can be installed on the first bearing cover 1281. The wave anti-detachment ring 141 prevents the bump foil 125 and the cover foil 126 from detaching in the axial direction.

[0298] The anti-slip ring 141 may be disposed on one side of the bump foil 125. The anti-slip ring 141 is disposed so as to protrude radially inward with respect to the inner peripheral surface of the first bearing cover 1281 on which the bump foil 125 is mounted.

[0299] An annular groove 142 may be formed in a radially recessed manner on one side of the first bearing cover 1281. The annular groove 142 is continuously formed along the inner circumferential surface of the first bearing cover 1281 in the circumferential direction.

[0300] The wave-proof ring 141 may be inserted and coupled to the annular groove 142. A portion of the wave-proof ring 141 is accommodated in the annular groove 142, and the wave-proof ring 141 may be formed to protrude from the annular groove 142 toward the rotating shaft 119.

[0301] The stopper 143 is formed to protrude from the inner circumferential surface of the first bearing housing 1281 toward the rotating shaft 119. The stopper 143 may be disposed on the opposite side to the wave prevention ring 141 along the axial direction.

[0302] The radial bearing 124 may be disposed between the limiting portion 143 and the wave prevention ring 141 .

[0303] The stopper 143 and the bump stop ring 141 are arranged to overlap with a portion of the bump foil 125 in the axial direction, thereby preventing the radial bearing 124 from moving in the axial direction.

[0304] With the inner circumferential surface of the first bearing cover 1281 on which the radial bearing 124 is mounted as a reference, the protruding height h1 of the limiting portion 143 is smaller than the height H of the bump foil 125 .

[0305] Here, the height H of the bump foil 125 refers to the distance from the inner peripheral surface of the first bearing cover 1281 to the top of the curved surface portion 1251 of the bump foil 125 in the radial direction toward the rotation shaft 119 .

[0306] The protruding height h1 of the stopper 143 refers to the length from the inner circumferential surface of the first bearing cover 128 to the upper end of the stopper 143 along the radial direction toward the rotating shaft 119 .

[0307] The protruding height h1 of the stopper 143 limits the maximum elastic deformation of the bump foil 125 in the radial direction. In addition, the protruding height h1 of the stopper 143 limits the radial movement distance of the rotating shaft 119.

[0308] According to such a configuration, the stopper 143 allows the bump foil 125 to elastically deform in the radial direction within a predetermined range, and even if an impact exceeding a predetermined level is applied to the radial bearing 124 , damage to the bearing due to plastic deformation can be prevented.

[0309] The protruding height h1 of the limiting portion 143 is greater than the protruding height h2 of the anti-fall-off ring 141 .

[0310] Here, the protruding height h2 of the wave protection ring 141 refers to the length of the highest position protruding toward the outside of the annular groove 142 of the circular cross-section of the ring body 1411 with the inner circumferential surface of the first bearing cover body 1281 as the reference.

[0311] If the protruding height h1 of the limiting portion 143 is smaller than the protruding height h2 of the anti-slip ring 141 , when the rotating shaft 119 moves radially, the rotating shaft 119 may contact the anti-slip ring 141 before the limiting portion 143 .

[0312] Therefore, the rotating shaft 119 may come into contact with the wave prevention ring 141 and cause scratches or other damages.

[0313] Therefore, the limiting portion 143 prevents the rotating shaft 119 from contacting the anti-slip ring 141 when the rotating shaft 119 moves radially, thereby avoiding damage to the rotating shaft 119.

[0314] The stopper 143 includes a wear-resistant coating such as PTFE (Polytetrafluoroethylene).

[0315] Such a stopper 143 has a self-lubricating property by forming a wear-resistant coating on the outer surface, so that the rotation shaft 119 will not be damaged even if it contacts the rotation shaft 119 .

[0316] The protruding height h1 of the stopper 143 may be formed to be in the range of 40-50% of the wave height H. The wave coil may be elastically deformed in the range of 50-60% of the wave height H.

[0317] When the protruding height h1 of the stopper 143 exceeds 50% of the wave height H, the elastic deformation range of the radial bearing 124 is reduced, so there is a disadvantage that the radial movable range of the rotating shaft 119 is reduced.

[0318] When the protruding height h1 of the limit portion 143 is less than 40% of the wave height H, if it is smaller than the protruding height h2 of the anti-wave disengagement ring 141, when the rotating shaft 119 moves radially, it contacts the anti-wave disengagement ring 141 before the limit portion 143, thereby causing the problem of damage to the rotating shaft 119.

[0319] The position limiting portion 143 may be formed integrally with the first bearing cover 1281, or may be provided separately from the first bearing cover 1281 and combined with the first bearing cover 1281. In this embodiment, the position limiting portion 143 is formed integrally with the first bearing cover 1281.

[0320] The wave-proof ring 141 and the stopper 143 of the present invention can also be applied to the radial bearing 124 of the first bearing and the radial bearing 124 of the second bearing. The radial bearing 124 of the second bearing is the same or similar to the radial bearing 124 of the first bearing, so repeated description is omitted.

[0321] The limiting portion 143 may be composed of a first limiting portion and a second limiting portion.

[0322] The first limiting portion may be disposed on one side of the radial bearing 124 , and the second limiting portion may be disposed on the other side of the radial bearing 124 .

[0323] The radial bearing 124 may be disposed between the first limiting portion and the second limiting portion.

[0324] The first limiting portion and the second limiting portion may be formed to protrude from the inner circumferential surface of the bearing cover body 128 toward the rotating shaft 119 .

[0325] The first limiting portion and the second limiting portion may be in contact with the rotating shaft 119 .

[0326] The first limiting portion and the second limiting portion can limit the radial movement range of the rotating shaft 119 to the elastic deformation range of the radial bearing 124 .

[0327] The first stopper and the second stopper can prevent the radial bearing 124 from axially disengaging from the inner circumferential surface of the bearing cover 128. In this case, the anti-disengagement ring 141 can be omitted.

[0328] The first limiting portion and the second limiting portion have outer surfaces formed with a wear-resistant coating such as PTFE.

[0329] (3) Radial bearing safety device 2

[0330] Figure 6 This is a conceptual diagram of a radial bearing safety device 2 according to another embodiment of the present invention installed on a first bearing cover 1281, viewed along the axial direction.

[0331] Figure 7 is along Figure 6 A cross-sectional view taken along line VII-VII.

[0332] Figure 8 Yes Figure 7 An enlarged view of part VIII is shown.

[0333] and Figure 5 Compared with the embodiment of the present invention, the present embodiment is different in that a limiting ring 144 is installed on the first bearing cover 1281.

[0334] The limiting ring 144 may be formed in a circular ring shape, a closed loop shape, or may extend continuously along the circumferential direction.

[0335] The limiting ring 144 includes a limiting ring 144 body 1411 in a closed loop form and an axis through hole formed inside the limiting ring 144 body 1411. The diameter of the axis through hole of the limiting ring 144 may be larger than the diameter of the rotating shaft 119. The limiting ring 144 body 1411 may have a circular cross-sectional shape.

[0336] The limiting ring 144 may be composed of a first limiting ring 1441 and a second limiting ring 1442. The first limiting ring 1441 and the second limiting ring 1442 may be spaced apart in the axial direction. The radial bearing 124 may be disposed between the first limiting ring 1441 and the second limiting ring 1442.

[0337] A first ring installation groove 1451 and a second ring installation groove 1452 are recessed in the first bearing housing 1281. The first ring installation groove 1451 and the second ring installation groove 1452 are axially spaced apart from each other on the inner peripheral surface of the first bearing housing 1281 where the radial bearing 124 is installed.

[0338] The first limiting ring 1441 is installed in the first ring installation groove 1451 , and the second limiting ring 1442 is installed in the second ring installation groove 1452 .

[0339] A portion of the limiting ring 144 may be accommodated in the ring installation groove, and another portion of the limiting ring 144 may protrude outward from the ring installation groove.

[0340] With the inner peripheral surface of the first bearing cover 1281 on which the radial bearing 124 is mounted as a reference, the protruding height h1 of the stop ring 144 is smaller than the height H of the air foil bearing (bump foil 125 ).

[0341] The limiting ring 144 protrudes further toward the rotating shaft 119 than the inner circumferential surface of the first bearing cover 100 , thereby limiting the axial movement of the radial bearing 124 .

[0342] Even if the radial movement of the rotating shaft 119 exerts an impact on the bump foil 125 of the radial bearing 124 , the limit ring 144 can limit the radial movement distance of the rotating shaft 119 to the elastic deformation range of the radial bearing 124 .

[0343] In this embodiment, an example is shown in which the first limiting ring 1441 and the second limiting ring 1442 are arranged on both sides of the radial bearing 124. However, it is not limited thereto, and the limiting ring 144 may be arranged on one side of the radial bearing 124, and the wave anti-slip ring 141 may be arranged on the other side of the radial bearing 124.

[0344] In this case, with the inner circumferential surface of the first bearing cover 1281 as a reference, the protruding height h1 of the limit ring 144 is smaller than the height H of the corrugated foil 125 of the radial bearing 124 , and is larger than the height h2 of the corrugated anti-detachment ring 141 .

[0345] Preferably, the protruding height h1 of the limiting ring 144 is 40-50% of the height H of the bump foil 125 of the radial bearing 124. An anti-wear coating is formed on the outer surface of the limiting ring 144.

[0346] The ring mounting grooves 1451 , 1452 may be disposed adjacent to one end of the inner circumferential surface of the bearing cover body 128 .

[0347] The first ring mounting groove 1451 may be formed at the front end portion of the inner circumferential surface of the bearing cover body 128 facing the impeller 123 , and the second ring mounting groove 1452 may be formed at the rear end portion of the inner circumferential surface of the bearing cover body 128 facing the opposite direction of the impeller 123 .

[0348] According to such a structure, when the ring mounting grooves 1451 and 1452 are arranged adjacent to one end of the inner circumferential surface of the bearing cover body 128, the limit ring 144 can be easily assembled into or removed from the ring mounting grooves 1451 and 1452.

[0349] In addition, a chamfered portion 146 may be formed at one end of the inner circumferential surface of the bearing housing 128. The ring mounting grooves 1451 and 1452 may be disposed adjacent to the chamfered portion 146. Thus, the stop ring 144 may be easily assembled to or removed from the ring mounting grooves 1451 and 1452 through the chamfered portion 146.

[0350] A radial seal receiving groove 131 for receiving the first radial seal 130 is formed on the front surface of the first bearing cover 1281 .

[0351] An O-ring installation groove 148 is formed on the inner side of the radial seal portion receiving groove 131. An O-ring is installed in the O-ring installation groove 148, so that the airtightness between the first radial seal portion 130 and the first bearing cover 1281 can be maintained.

[0352] A fastening hole 149 may be formed at the outer circumference of the first bearing cover 1281. The fastening hole 149 is formed to penetrate in the axial direction. A fastening member such as a screw may be fastened through the fastening hole 149. The fastening member may fasten the first bearing cover 1281 to the cover 100.

[0353] Other components and Figures 1 to 5 The embodiments are the same or similar, so repeated description is omitted.

[0354] (4) Radial bearing safety device 3

[0355] Fig. 9 This is a conceptual diagram of a situation where a radial bearing safety device 3 according to another embodiment of the present invention is installed on a first bearing cover 1281 as viewed along the axial direction.

[0356] Fig.10 Yes Fig. 9 The X portion is enlarged to show the enlarged view.

[0357] and Figures 1 to 8 Compared with the embodiment of the present invention, the present embodiment is different in that a ball bearing 150 is used as a safety device for preventing the radial bearing 124 from being damaged.

[0358] The ball bearing 150 may be formed in a sphere shape. A plurality of ball bearings 150 may be provided.

[0359] A ball receiving groove 151 is formed on the inner circumferential surface of the first bearing cover 1281. The ball receiving groove 151 surrounds and supports the ball bearing 150. A plurality of ball receiving grooves 151 are provided.

[0360] The plurality of ball bearings 150 may be composed of a first ball bearing 1501 and a second ball bearing 1502 .

[0361] The first ball bearing 1501 and the second ball bearing 1502 may be arranged to be spaced apart in the axial direction via the radial bearing 124 on the inner peripheral surface of the first bearing cover 1281 .

[0362] The plurality of ball bearings 150 may be arranged at equal intervals in the circumferential direction.

[0363] In this embodiment, the ball bearings 150 are shown as a group of three ball bearings, namely, the first ball bearing 1501 and the second ball bearing 1502. The three groups of ball bearings 150 may be arranged at intervals of 120 degrees along the circumferential direction.

[0364] Other components and Figures 1 to 8 The embodiments are the same or similar, so repeated description is omitted.

[0365] (5) Radial bearing safety device 4

[0366] Fig.11 This is a conceptual diagram of a situation where a radial bearing safety device 4 according to another embodiment of the present invention is installed on a first bearing cover 1281 as viewed along the axial direction.

[0367] Fig.12 Yes Fig.11 An enlarged view of the part XII is shown.

[0368] and Figures 1 to 8 Compared with the embodiment of the present invention, the present embodiment is different in that a needle roller bearing 152 is used as a safety device for preventing the radial bearing 124 from being damaged.

[0369] The needle roller bearing 152 may be formed in the form of a cylindrical roller having a length longer than a diameter. A plurality of needle roller bearings 152 may be provided.

[0370] The plurality of needle roller bearings 152 may include a first needle roller bearing 1521 and a second needle roller bearing 1522 .

[0371] The first needle roller bearing 1521 and the second needle roller bearing 1522 may be arranged axially spaced apart from each other on the inner peripheral surface of the first bearing cover 1281 via the radial bearing 124 .

[0372] A needle roller receiving groove 153 is formed on the inner peripheral surface of the first bearing cover 1281. The needle roller receiving groove 153 surrounds and supports the needle roller bearing 152. A plurality of needle roller receiving grooves 153 are provided.

[0373] The needle bearings 152 may be provided in a plurality of groups, with the first needle bearing 1521 and the second needle bearing 1522 forming a group. The plurality of needle bearings 152 may be arranged at equal intervals along the circumferential direction.

[0374] Other components and Figures 1 to 10 The embodiments are the same or similar, so repeated description is omitted.

[0375] In the above Figures 6 to 11 In the embodiment of the radial bearing safety device, the limit ring 144, the ball bearing 150 and the needle bearing 152 are respectively arranged on one side and the other side of the radial bearing 124, but any one of the limit ring 144, the ball bearing 150 and the needle bearing 152 and the anti-slip ring can also be respectively set on one side and the other side of the radial bearing 124.

[0376] In addition, the safety device may be composed of a combination of two different safety devices selected from the stopper 143 , the stopper ring 144 , the ball bearing 150 , and the needle bearing 152 .

[0377] Therefore, according to the present invention, the radial bearing 124 includes an air foil bearing mounted on the inner peripheral surface of the bearing housing 128 , thereby separating an air gap from the rotating shaft 119 and supporting the radial load of the rotating shaft 119 .

[0378] The radial bearing safety device is provided on the inner peripheral surface of the bearing cover 128. The radial bearing safety device limits the radial movable range of the rotating shaft 119 to the elastic deformation range of the radial bearing 124.

[0379] As an embodiment, the stopper 143 is formed to protrude from the inner circumferential surface of the bearing cover 128 toward the rotating shaft 119. The stopper 143 can contact the rotating shaft 119 to limit the radial movement of the rotating shaft 119. Therefore, as the stopper 143 limits the radial movement distance of the rotating shaft 119, when the radial bearing 124 supports the radial load of the rotating shaft 119, even if the rotating shaft 119 performs abnormal operation due to abnormal operation caused by external impact or liquid refrigerant, etc., the radial bearing 124 can be prevented from plastic deformation.

[0380] In addition, the stopper 143 protrudes from the inner peripheral surface of the bearing cover 128 and is formed integrally, so there is no need to assemble additional parts for preventing damage to the radial bearing 124. Therefore, the number of parts and the number of assembly steps can be reduced, which also greatly contributes to reducing manufacturing costs.

[0381] Furthermore, the stopper 143 is formed to be a structure protruding from the inner peripheral surface of the bearing cover 128, so the durability can be improved by simplifying the structure.

[0382] In addition, the protruding height h1 of the limit portion 143 protruding from the inner circumferential surface of the bearing cover body 128 is smaller than the wave height H from the inner circumferential surface of the bearing cover body 128 along the radial direction to the vertex of the curved portion 1251 of the air foil bearing, and is larger than the height h2 of the wave anti-slip ring 141 protruding from the annular groove 142 toward the rotating shaft 119 based on the inner circumferential surface of the bearing cover body 128.

[0383] Therefore, even when the rotating shaft 119 moves abnormally, the radial movement of the rotating shaft 119 is stopped by the limit portion 143 before the rotating shaft 119 contacts the anti-slip ring 141, thereby preventing the rotating shaft 119 from being damaged due to the contact between the rotating shaft 119 and the anti-slip ring 141.

[0384] In particular, as another embodiment of the radial bearing safety device, a limit ring 144, a ball bearing 150, and a needle bearing 152 may be used.

[0385] A groove is formed on the inner circumferential surface of the bearing cover 128 to engage the stop ring 144, the ball bearing 150 and the needle bearing 152. The groove is arranged adjacent to the front end or rear end of the inner circumferential surface of the bearing cover 128, so that the stop ring 144, the ball bearing 150 and the needle bearing 152 can be easily assembled or disassembled into or from the groove.

[0386] Moreover, the ball bearing 150 and the needle bearing 152 are arranged circumferentially spaced apart along the inner circumference of the bearing cover 128. Thus, compared with the stop ring 144 extending circumferentially along the inner circumference of the bearing cover 128, the contact area between the ball bearing 150 and the needle bearing 152 and the rotating shaft 119 is reduced.

[0387] Therefore, even when the rotating shaft 119 moves abnormally due to external impact or the like, the ball bearing 150 or the needle bearing 152 is in point contact or line contact with the rotating shaft 119, thereby reducing the contact area, thereby minimizing damage to the radial bearing 124 and the rotating shaft 119.

[0388] In addition, the stopper 143 , the stopper ring 144 , the ball bearing 150 , and the needle bearing 152 have surfaces formed with a wear-resistant coating, thereby minimizing damage to the radial bearing 124 and the rotating shaft 119 caused by contact with the rotating shaft 119 .

[0389] In addition, the limiting portion 143 , the limiting ring 144 , the ball bearing 150 and the needle bearing 152 limit the radial movement range of the rotating shaft 119 within the elastic deformation range of the radial bearing 124 , thereby having the advantage of easy alignment between the radial bearing 124 and the rotating shaft 119 .

[0390] 3. Description of the structure of a turbo compressor according to another embodiment of the present invention

[0391] Hereinafter, various components of a turbo compressor according to another embodiment of the present invention will be described with reference to the drawings.

[0392] Fig.13 This is a conceptual diagram for explaining the structure of the turbo compressor of the present invention.

[0393] The turbo compressor of the present invention includes a housing 200 , an electric unit 220 , a rotating shaft 219 , an impeller 223 , impeller casings 211 , 212 , a bearing housing 228 , a thrust bearing 227 , and a radial bearing 224 .

[0394] (1) Compressor components

[0395] The cover body 200 may be formed in a cylindrical shape and may form the appearance of the turbo compressor.

[0396] Both sides of the cover 200 may be fastened to the impeller casings 211 , 212 .

[0397] An accommodation space is formed inside the housing 200. The accommodation space of the housing 200 may be divided into a first space 217 and a second space 218. The first space 217 and the second space 218 may be divided by a partition wall 216.

[0398] The partition wall 216 may be formed to protrude radially from the inner circumferential surface of the cover body 200 toward the rotating shaft 219. The partition wall 216 may extend in a circumferential direction along the inner circumferential surface of the cover body 200. The partition wall 216 may be formed in a disc shape with a preset thickness.

[0399] A shaft through hole may be formed in a central portion of the partition wall 216 so that the rotating shaft 219 can pass therethrough.

[0400] The partition wall 216 and the rotating shaft 219 are arranged to be spaced apart from each other at a predetermined interval in the radial direction.

[0401] The partition wall 216 may be disposed offset from the center of the cover body 200 in the longitudinal direction toward one direction.

[0402] The first space 217 may be open to one side of the cover body 200 , and the second space 218 may be open to the other side of the cover body 200 .

[0403] The volumes of the first space 217 and the second space 218 may be different from each other. The volume of the first space 217 may be smaller than the volume of the second space 218.

[0404] The electric part 220 described later can be accommodated in the second space 218 having a relatively large volume. A part of the first bearing cover 2281 described later can be accommodated in the first space 217. The second bearing cover 2282 described later can be accommodated in the second space 218.

[0405] The rotating shaft 219 may be horizontally disposed in the first space 217 and the second space 218 to axially cross a radial center portion of the housing 200 .

[0406] The electric part 220 includes a stator 221 and a rotor 222. The stator 221 has a stator core 2211 and a stator coil 2212. The stator core 2211 may be formed in a cylindrical shape by stacking and combining a plurality of electrical steel sheets.

[0407] The stator core 2211 may be formed such that a plurality of teeth protrude radially toward the rotating shaft 219 at the inner side of the stator core 2211. A plurality of slits may be formed between the plurality of teeth. The plurality of teeth and the plurality of slits may be alternately arranged along the circumferential direction of the stator core 2211 and spaced apart in the circumferential direction.

[0408] The stator coil 2212 is wound around the stator core 2211 through the slits.

[0409] If power is applied to the stator coil 2212 , a magnetic field is generated around the stator coil 2212 .

[0410] The rotor 222 is arranged inside the stator 221. The rotor 222 is arranged with an air gap between it and the stator 221. The rotor 222 is attached to the rotating shaft 219 so as to be rotatable relative to the stator 221.

[0411] The rotor 222 may include a rotor core and permanent magnets 2221. The rotor core may be installed to be rotatable together with the rotating shaft 219 or may be omitted. In the case where the rotor core is omitted, the permanent magnets 2221 may be installed to the rotating shaft 219.

[0412] The permanent magnet 2221 may be disposed on the rotating shaft 219 or the rotor core, and overlapped radially with the inner side surface of the stator 221 with an air gap therebetween. In this embodiment, the permanent magnet 2221 is attached to the rotating shaft 219.

[0413] A rotor support portion may be provided on the rotating shaft 219. The rotor support portion may be arranged at the center along the axial direction of the rotating shaft 219. The rotor support portion may be formed to be recessed or protruded in the radial direction of the rotating shaft 219.

[0414] The permanent magnet 2221 can be installed to be accommodated in the rotor support part, or can be fixed between multiple rotor support parts so that the axial movement is limited by the protruding rotor support part. In this embodiment, the rotor support part is formed to protrude radially from the rotating shaft 219, and the permanent magnet 2221 is arranged and fixed between multiple rotor support parts.

[0415] The permanent magnet 2221 is formed in a cylindrical ring shape. The inner diameter of the permanent magnet 2221 may have the same diameter as the diameter of the rotating shaft 219. The outer diameter of the permanent magnet 2221 may be formed to be smaller than the inner diameter of the stator 221 core.

[0416] According to such a configuration, when power is applied to the stator 221 , the rotor 222 can rotate relative to the stator 221 due to electromagnetic interaction between the stator 221 and the rotor 222 .

[0417] The rotating shaft 219 is configured to rotate together with the rotor 222 and transmit a rotational force to an impeller 223 described later.

[0418] Both ends of the rotating shaft 219 may be supported by bearings. The bearings include a first bearing and a second bearing.

[0419] The first bearing supports one side of the rotating shaft 219. The first bearing may be disposed between the electric part 220 and a primary impeller described later. The primary impeller may be referred to as a first impeller 2231.

[0420] The second bearing supports the other side of the rotating shaft 219. The second bearing may be disposed between the electric part 220 and a secondary impeller described later. The secondary impeller may be referred to as a second impeller 2232.

[0421] The bearing may include a radial bearing 224 supporting a radial load of the rotating shaft 219 and a thrust bearing 227 supporting an axial load of the rotating shaft 219 .

[0422] The first bearing may include a first radial bearing 2241 , a first thrust bearing 2271 , and a second thrust bearing 2272 .

[0423] The second bearing may include a second radial bearing 2242 .

[0424] The bearing cover 228 includes a first bearing cover 2281 and a second bearing cover 2282 .

[0425] The first bearing cover 2281 supports the first bearing. It should be noted that the second thrust bearing 2272 may be supported by the partition wall 216 .

[0426] The first bearing cover 2281 may be formed in a cylindrical shape. The first bearing cover 2281 may have a circular groove portion formed radially inward.

[0427] The first bearing cover 2281 may be disposed between the first impeller housing 211 and the partition wall 216 of the housing 200. A portion of the first bearing cover 2281 may be accommodated in the first space 217 of the housing 200, and another portion of the first bearing cover 2281 may be accommodated inside the first impeller housing 211.

[0428] The first bearing cover 2281 may be pressed into and coupled to the inner side of the first impeller housing 211 .

[0429] A first shaft hole is formed inside the first bearing cover 2281 so that the rotating shaft 219 passes therethrough. The first shaft hole is formed to be larger than the diameter of the rotating shaft 219.

[0430] The first bearing may be mounted on the first bearing cover 2281 .

[0431] The first radial bearing 2241 may be installed to be accommodated radially inside the first bearing housing 2281 .

[0432] The second bearing housing 2282 may include a bearing receiving portion and a radially extending portion.

[0433] A cylindrical second shaft hole is provided inside the bearing accommodation portion. The rotating shaft 219 passes through the second shaft hole in the axial direction. The outer peripheral surface of the bearing accommodation portion may be formed to be inclined relative to the axial direction.

[0434] The second radial bearing 2242 may be installed on the inner side of the bearing receiving portion. The second radial bearing 2242 is spaced apart from the rotating shaft 219 with a gap in the radial direction.

[0435] The radially extending portion may protrude and extend from the outer circumference of the bearing accommodation portion toward the radial outside. The radially extending portion may extend along the circumferential direction in a disc shape.

[0436] The radially extending portion may be coupled to the inner side of the other end portion of the cover body 200 .

[0437] The bearing accommodation portion may protrude from the radially extending portion toward the second space 218 of the cover body 200 in the axial direction.

[0438] According to such a configuration, the first radial bearing 2241 and the second radial bearing 2242 can support the radial load of the rotating shaft 219 .

[0439] The first thrust bearing 2271 may be mounted on the axial back side of the first bearing cover 2281 .

[0440] A thrust mirror plate 229 is provided on the rotating shaft 219. The thrust mirror plate 229 may be formed to protrude radially from the rotating shaft 219 toward the first space 217. The thrust mirror plate 229 may rotate together with the rotating shaft 219.

[0441] The first thrust bearing 2271 may be spaced apart from one axial side surface of the thrust mirror plate 229 by a gap in the axial direction.

[0442] The second thrust bearing 2272 may be mounted on the partition wall 216. The second thrust bearing 2272 may be disposed on the opposite side of the first thrust bearing 2271 with the thrust mirror plate 229 interposed therebetween.

[0443] The second thrust bearing 2272 may be spaced apart from the other axial side surface of the thrust mirror plate 229 by a gap in the axial direction.

[0444] The first thrust bearing 2271 and the second thrust bearing 2272 can support the axial load of the rotating shaft 219 via the thrust mirror plate 229 .

[0445] The radial bearing 224 and the thrust bearing 227 of this embodiment can be implemented by air foil bearings respectively.

[0446] The air foil bearing supports the rotating shaft 219 using working fluid.

[0447] The working fluid may be a refrigerant or air, etc. In this embodiment, the working fluid may be a refrigerant.

[0448] The air foil bearing may be arranged to be spaced apart from the rotating shaft 219 by a predetermined interval (air gap).

[0449] The air foil bearing can rotatably support the rotating shaft 219 using a working fluid that fills a gap between the rotating shaft 219 and the bearing.

[0450] The bearing of the present invention is configured to be separated from the rotating shaft 219, and can support the rotating shaft 219 in a non-contact manner so that it can rotate. Accordingly, as the rotating shaft 219 rotates at high speed, an air gap is stably formed between the rotating shaft 219 and the bearing, and the center of the rotating shaft 219 is located at the center of the bearing. When the rotation speed is further increased, under the action of centrifugal force, the pressure of the air gap rises and the shaft supporting force increases, thereby realizing a frictionless and efficient compressor. In addition, the noise is small and the wear is reduced, so that the life of the bearing can be extended. In addition, the bearing of the present invention does not require lubricating oil, so there is no need to replace the lubricating oil, and no maintenance and management costs are incurred.

[0451] Fig.14 It shows the axial direction Fig.13 A conceptual diagram of the thrust bearing 227 in FIG.

[0452] Fig.15 is along Fig.14 A cross-sectional view taken along the XV-XV line (circumferential curve).

[0453] The thrust bearing 227 may be implemented by an air foil bearing and may be arranged to overlap with the thrust mirror plate 229 along the axial direction.

[0454] According to the setting position, the thrust bearing 227 may be composed of a first thrust bearing 2271 and a second thrust bearing 2272 .

[0455] The first thrust bearing 2271 may be mounted on the back side of the first bearing cover 2281. The front side of the first bearing cover 2281 faces the first impeller 2231, and the back side of the first bearing cover 2281 faces the thrust mirror plate 229.

[0456] The second thrust bearing 2272 may be mounted on the front side of the partition wall 216. The front side of the partition wall 216 faces the thrust mirror plate 229, and the back side of the partition wall 216 faces the electric unit 220.

[0457] The first thrust bearing 2271 and the second thrust bearing 2272 are arranged to be spaced apart from the thrust mirror plate 229 at a predetermined interval in the axial direction.

[0458] The description regarding the thrust bearing 227 may be equally applied to the first thrust bearing 2271 and the second thrust bearing 2272 .

[0459] The thrust bearing 227 includes a bump foil 2273 , a cover foil 2274 , and a bearing plate 2278 .

[0460] The bump foil 2273 is an elastic structure and can be formed by forming a metal thin film into an embossed form.

[0461] One side of the bump foil 2273 may be fixed to the bearing plate 2278 , and the other side of the bump foil 2273 may be a free end.

[0462] The bump foil 2273 may include a plurality of curved surface portions 2273 a and a plurality of connecting portions 2273 b .

[0463] The curved surface portion 2273a may be formed in an arc shape or a semicircular shape. The connecting portion 2273b is formed in a flat shape.

[0464] The connection portion 2273b is configured to connect one end and the other end of two adjacent curved surface portions 2273a.

[0465] The plurality of curved surface portions 2273a and the plurality of connecting portions 2273b are alternately arranged in one direction. The plurality of curved surface portions 2273a and the connecting portion 2273b may be formed as one body. In this embodiment, the plurality of curved surface portions 2273a and the plurality of connecting portions 2273b are alternately arranged in the circumferential direction of the thrust bearing 227.

[0466] The plurality of curved surface portions 2273a may be formed to have the same radius.

[0467] The plurality of curved surface portions 2273 a may be formed to protrude in the same direction. The plurality of curved surface portions 2273 a may be formed to protrude from the bearing plate 2278 toward the cover foil 2274 .

[0468] The multiple curved surface portions 2273a can be formed to protrude in which direction according to the axial load supporting direction of the bearing.

[0469] For example, in the case of the thrust bearing 227 , the curved surface portion 2273 a may be formed to protrude in the axial direction, and in the case of the radial bearing, the curved surface portion 2273 a may be formed to protrude in the radial direction.

[0470] The curved surface portion 2273 a of the thrust bearing 227 may be formed to protrude in the axial direction.

[0471] The cover foil 2274 is configured to cover the bump foil 2273. Since the cover foil 2274 is configured to be able to contact the highest apex of the bump foil 2273, it can be called a top foil.

[0472] The cover foil 2274 is disposed facing the thrust mirror plate 229 and is spaced apart from the thrust mirror plate 229 in the axial direction.

[0473] The cover foil 2274 may be composed of a cover extending portion 2275 , a cover inclined portion 2276 , and a cover fixing portion 2277 .

[0474] The cover extension portion 2275 is arranged so as to be able to come into contact with the highest vertex of the curved surface portion 2273 a of the bump foil 2273 .

[0475] The cover fixing portion 2277 is configured in a planar form to fix the cover foil 2274 to the base plate.

[0476] The cover inclined portion 2276 may be formed to be inclined at a preset angle with respect to the bearing plate 2278 to connect the cover extending portion 2275 and the cover fixing portion 2277 .

[0477] The bearing plate 2278 is configured to fix the thrust bearing 227 to the first bearing cover 2281 or the partition wall 216 .

[0478] The cover fixing portion 2277 of the cover foil 2274 is fixed to the bearing plate 2278 , and the cover extending portion 2275 of the cover foil 2274 is a free end.

[0479] The bearing plate 2278 may be formed as a circular plate. A through hole is formed in the bearing plate 2278 so that the rotating shaft 219 can pass through. The through hole of the bearing plate 2278 is formed to be larger than the diameter of the rotating shaft 219.

[0480] When the bearing plate 2278 is divided into six equal parts along the circumferential direction, the cover foil 2274 may be formed in a fan-shaped form having a size slightly smaller than 1 / 6 of the size of the bearing plate 2278. A plurality of cover foils 2274 may be spaced along the circumferential direction of the bearing plate 2278 and one side of each cover foil 2274 may be fixed to the bearing plate 2278. However, the size of the cover foil 2274 is not limited thereto.

[0481] The plurality of bump foils 2273 may be disposed inside the cover foil 2274 divided into six equal parts along the circumferential direction of the bearing plate 2278. The bump foil 2273 may extend along the circumferential direction of the bearing plate 2278.

[0482] A plurality of bump foils 2273 may be arranged spaced apart in the radial direction of the bearing plate 2278. It should be noted that the bump foil 2273 may be formed to correspond to the size of the cover foil 2274, and each cover foil 2274 may be provided with one bump foil 2273.

[0483] According to such a configuration, even if the axial load transmitted to the rotating shaft 219 due to the refrigerant suction pressure of the impeller 223 acts on the thrust mirror plate 229, the first thrust bearing 2271 and the second thrust bearing 2272 can use the elastic force of the bump foil 2273 to support the axial load of the rotating shaft 219 in a rotatable manner.

[0484] The turbo compressor can compress the refrigerant in multiple stages according to the number of impellers 223. In this embodiment, a case where it is configured as a two-stage compressor is shown.

[0485] The impeller 223 can be divided into the first impeller 2231 to the Nth impeller according to the compression order of the refrigerant. In this embodiment, the impeller 223 is composed of the first impeller 2231 and the second impeller 2232. The first impeller 2231 can be called a primary impeller, and the second impeller 2232 can be called a secondary impeller.

[0486] In the present specification, the description of the structure of the impeller 223 can also be applied to the first impeller 2231 and the second impeller 2232 without separately distinguishing between the first impeller 2231 and the second impeller 2232 .

[0487] Fluids such as refrigerant and / or air can be compressed in the first impeller 2231 and then compressed in the second impeller 2232 (recompressed).

[0488] The impeller 223 is mounted on the rotating shaft 219 so as to be rotatable together with the rotating shaft 219. The impeller 223 can receive power from the electric unit 220 through the rotating shaft 219 to rotate.

[0489] The impeller 223 sucks a fluid such as a refrigerant to compress the fluid such as the refrigerant while rotating with the rotating shaft 219 .

[0490] A first impeller support portion and a second impeller support portion may be provided at both ends of the rotating shaft 219 .

[0491] The first impeller support portion has a diameter smaller than that of the rotating shaft 219 and may be formed to protrude in the axial direction from one end of the rotating shaft 219. The first impeller support portion may be press-fitted into the inner side of the hub 223a coupled to the first impeller 2231.

[0492] The second impeller support portion has a diameter smaller than that of the rotation shaft 219 and may be formed to protrude in the axial direction from the other end of the rotation shaft 219. The second impeller support portion may be press-fitted into the inner side of the hub 223a coupled to the second impeller 2232.

[0493] The impeller 223 includes a hub 223a and a plurality of blades 223b.

[0494] A through hole is provided inside the hub 223a so that the rotating shaft 219 passes through. The hub 223a may be formed in a conical shape. The outer peripheral surface of the hub 223a may be formed to be inclined relative to the axial direction. With the suction direction of the working fluid as a reference, the diameter of the hub 223a may gradually increase as it approaches the axial rear end of the hub 223a from the axial front end of the hub 223a.

[0495] The plurality of blades 223b may be formed to protrude in a spiral shape on the outer peripheral surface of the hub 223a. The plurality of blades 223b may be arranged to be spaced apart in the circumferential direction of the hub 223a.

[0496] According to such a configuration, the impeller 223 can suck in a gas such as a refrigerant in the axial direction and discharge the sucked gas in a centrifugal direction of the impeller 223 .

[0497] The first impeller housing 211 is fastened to one side of the housing 200. The axial back side of the first impeller housing 211 may be covered by a first bearing housing 2281 accommodated in one side of the housing 200.

[0498] The second impeller housing 112 is fastened to the other side of the housing 200. The axial back side of the second impeller housing 112 may be covered by a second bearing housing 2282 accommodated on the other side of the housing 200. The axial back sides of the first impeller housing 211 and the second impeller housing 112 refer to the downstream side of the impeller housing based on the flow direction of the refrigerant.

[0499] The first impeller casing 211 includes suction ports 213 a and 213 b , guide vanes 214 a and 214 b , and discharge ports 215 a and 215 b .

[0500] The suction ports 213a and 213b are formed axially through the center of the first impeller housing 211. One side of the suction ports 213a and 213b can communicate with the outside of the first impeller housing 211, and the other side of the suction ports 213a and 213b can communicate with the inside of the first impeller housing 211.

[0501] The first impeller 2231 is accommodated inside the suction ports 213a and 213b. The first impeller 2231 may be mounted on the first impeller support portion to rotate together with the rotation shaft 219.

[0502] The suction ports 213a and 213b may be formed so that the diameter thereof decreases as it approaches the other side in the axial direction from the one side in the axial direction. Thus, the flow rate of the refrigerant sucked through the suction ports 213a and 213b may be increased.

[0503] The guide vanes 214a and 214b are formed to be recessed in the axial direction on the axial back side of the first impeller housing 211. The guide vanes 214a and 214b are formed inside the first impeller housing 211. The guide vanes 214a and 214b are arranged between the suction ports 213a and 213b and the discharge ports 215a and 215b.

[0504] The guide vanes 214a and 214b may be formed to extend from the suction ports 213a and 213b in a spiral direction. The guide vanes 214a and 214b are connected to the suction ports 213a and 213b and the discharge ports 215a and 215b so as to communicate with each other. The guide vanes 214a and 214b are formed so that the size of the flow path increases as the suction ports 213a and 213b approach the discharge ports 215a and 215b.

[0505] According to such a configuration, as the size of the flow path of the guide vanes 214a and 214b increases, the working fluid sucked in by the rotation of the impeller 223 increases in pressure while passing through the guide vanes 214a and 214b.

[0506] That is, the guide vanes 214a and 214b can increase the pressure of the refrigerant by converting the kinetic energy of the refrigerant sucked through the suction ports 213a and 213b into pressure energy.

[0507] The discharge ports 215a and 215b are provided at the outer peripheral portion of the first impeller housing 211. The discharge ports 215a and 215b may extend radially from the guide vanes 214a and 214b. The discharge pipe may be formed to protrude outward from the outer peripheral portion of the first impeller housing 211.

[0508] One side of the discharge pipe communicates with the discharge ports 215 a and 215 b , and the other side of the discharge pipe may communicate with the outside of the first impeller casing 211 .

[0509] The second impeller housing 112 includes suction ports 213a, 213b, guide vanes 214a, 214b, and discharge ports 215a, 215b. The suction ports 213a, 213b, guide vanes 214a, 214b, and discharge ports 215a, 215b of the second impeller housing 112 are the same as or similar to the suction ports 213a, 213b, guide vanes 214a, 214b, and discharge ports 215a, 215b of the first impeller housing 211, and therefore, repeated descriptions are omitted.

[0510] It should be noted that, in order to perform two-stage compression, the discharge pipe of the first impeller casing 211 and the suction ports 213 a and 213 b of the second impeller casing 112 may be connected via a connecting pipe (not shown).

[0511] The first impeller housing 211 and the second impeller housing 112 may each be separably formed of two parts.

[0512] One part is a suction part 211a, 212a. The suction part 211a, 212a may be formed to have a T-shaped cross-sectional shape. The suction part 211a, 212a may be composed of a radial part extending in the radial direction and an axial part extending in the axial direction. The suction ports 213a, 213b are formed on the inner side of the axial part of the suction part 211a, 212a.

[0513] The downstream side portion of the suction portion 211 a , 212 a may be formed in a curved surface form of an arc shape. The downstream side portion of the suction portion 211 a , 212 a accommodates the impeller 223 .

[0514] The other part is the guide vane portion 211b, 212b. The guide vane portion 211b, 212b surrounds the outer circumference and back surface of the radial portion of the suction portion 211a, 212a and the outer circumference of the axial portion. The suction portion 211a, 212a and the guide vane portion 211b, 212b are combined with each other.

[0515] The back surface of the radial portion of the suction portions 211 a and 212 a refers to a downstream side surface based on the refrigerant suction direction.

[0516] In order to prevent refrigerant leakage, radial sealing members and axial sealing members are provided.

[0517] The radial sealing member may be disposed between the bearing housing 228 and the impeller 223. In this embodiment, a radial sealing member is disposed between the first bearing housing 2281 and the impeller 223.

[0518] The radial sealing member may be composed of a first radial sealing portion 230 and a second radial sealing portion 234 .

[0519] For example, a first radial sealing portion 230 may be provided on an axial side surface of the first bearing cover body 2281 .

[0520] The first radial sealing portion 230 may be integrally formed on an axial side surface of the first bearing cover body 2281 , or may be combined with an axial side surface of the first bearing cover body 2281 .

[0521] In this embodiment, the first radial seal 230 is combined with an axial side surface of the first bearing housing 2281. To this end, a seal receiving groove 231 may be formed in an axial direction on an axial side surface of the first bearing housing 2281 to receive the first radial seal 230.

[0522] The first radial sealing portion 230 includes a plurality of sealed grooves 232 and a plurality of first base portions 233 .

[0523] The plurality of sealed grooves 232 may be formed on one axial side (front side) of the first radial sealing portion 230 and may be recessed in the axial direction in the opposite direction from the impeller 223. The plurality of sealed grooves 232 may extend in the circumferential direction of the first radial sealing portion 230.

[0524] The front side of the first radial seal portion 230 refers to a side facing the impeller 223 .

[0525] The plurality of sealed grooves 232 may be arranged spaced apart in the radial direction of the first radial sealing portion 230 .

[0526] The plurality of sealed grooves 232 may be arranged to overlap with the impeller 223 along the axial direction.

[0527] The plurality of first base portions 233 may be disposed between the plurality of sealed grooves 232 .

[0528] The plurality of sealed grooves 232 and the plurality of first base portions 233 may be alternately arranged along the radial direction of the first radial sealing portion 230 .

[0529] The plurality of sealed grooves 232 and the plurality of first base portions 233 may be formed in a ring shape, respectively. However, the radial width of the sealed groove 232 and the radial thickness of the first base portion 233 may be formed to be different from each other.

[0530] A second radial sealing portion 234 may be provided on the other axial side (back side) of the first impeller 2231. The back side of the first impeller 2231 is the side facing the first radial sealing portion 230.

[0531] The second radial seal portion 234 is disposed on the downstream side of the first impeller 2231 based on the flow direction of the refrigerant. The second radial seal portion 234 can rotate together with the first impeller 2231.

[0532] The second radial sealing portion 234 includes a plurality of sealing protrusions 235 .

[0533] A plurality of sealing protrusions 235 are formed to protrude axially from the other axial side surface of the hub 223a of the first impeller 2231 toward the first radial sealing portion 230. The plurality of sealing protrusions 235 can be respectively received in the plurality of sealing grooves 232.

[0534] The sealing protrusion 235 is accommodated in the sealing groove 232 and is arranged to be spaced apart from the inner side surface of the sealing groove 232 at a predetermined interval in the axial direction and the radial direction.

[0535] The sealing protrusion 235 extends in the circumferential direction of the hub 223 a and may be formed in a ring shape.

[0536] The plurality of sealing protrusions 235 and the plurality of first base portions 233 may be arranged to overlap in the radial direction.

[0537] According to such a configuration, by arranging the plurality of sealing protrusions 235 and the plurality of first base portions 233 to overlap in the radial direction, it is possible to prevent the refrigerant discharged from the impeller 223 to the guide vanes 214 a and 214 b from leaking.

[0538] For example, when the impeller 223 rotates, the plurality of blades 223 b rotate around the hub 223 a , so that the impeller 223 can discharge the refrigerant sucked through the spaces between the plurality of blades 223 b toward the guide vanes 214 a and 214 b in the radial direction.

[0539] Here, the multiple sealed protrusions 235 and the first base portion 233 act as flow resistance for the refrigerant flowing from the guide vanes 214a, 214b toward the downstream side of the impeller 223, thereby preventing the refrigerant from flowing radially inward through the gap between the sealed groove 232 of the first radial sealing portion 230 and the back side of the impeller 223.

[0540] In addition, the above-mentioned radial sealing component can also be similarly applied between the second bearing cover 2282 and the second impeller 2232.

[0541] The axial sealing member may be disposed between the second bearing housing 2282 and the second impeller housing 112. The axial sealing member may be composed of a first axial sealing portion 236 and a second axial sealing portion.

[0542] The first axial seal portion 236 may be disposed inside the guide vane portions 211b, 212b of the second impeller housing 112. The first axial seal portion 236 may be coupled between the second bearing cover 2282 and the guide vane portions 211b, 212b of the second impeller housing 112.

[0543] The first axial sealing portion 236 includes a plurality of sealing grooves. The plurality of sealing grooves may be recessed in the radial direction from the inner side surface of the first axial sealing portion 236, more specifically, from the inner side surface of the bearing accommodation portion.

[0544] The sealing groove may be formed in a ring shape and may extend in a circumferential direction along an inner peripheral edge of the first axial sealing portion 236 .

[0545] The plurality of sealing grooves may be arranged axially spaced apart on the inner side of the first axial sealing portion 236. A second base portion may be arranged between the plurality of sealing grooves. The plurality of sealing grooves and the plurality of second base portions may be arranged axially alternately spaced apart on the inner side surface of the first axial sealing portion 236.

[0546] The second axial sealing portion may be disposed on the other side of the rotating shaft 219. The second axial sealing portion may rotate together with the first impeller 2231. The second axial sealing portion may overlap with the sealing groove in the radial direction so as to be accommodated in the sealing groove.

[0547] The second axial sealing portion includes a plurality of sealing protrusions.

[0548] The plurality of sealing protrusions may be formed to protrude radially outward from the outer circumferential surface of the rotating shaft 219 toward the inner side surface of the sealing groove. The plurality of sealing protrusions may be formed in a ring shape.

[0549] The plurality of sealing protrusions are arranged on the rotating shaft 219 at intervals in the axial direction.

[0550] The plurality of sealing protrusions and the plurality of second base portions may be alternately arranged along the axial direction of the rotating shaft 219. The plurality of sealing protrusions and the plurality of second base portions are arranged to be spaced apart from each other at predetermined intervals along the axial direction.

[0551] The plurality of second base portions are spaced apart from the rotation shaft 219 at predetermined intervals in the radial direction.

[0552] The plurality of sealing protrusions are arranged radially apart from the inner side surface of the first axial sealing portion 236 at predetermined intervals.

[0553] The plurality of sealing protrusions and the second base portion are arranged to overlap in the axial direction.

[0554] According to such a configuration, by arranging the plurality of sealing protrusions and the second base portion to overlap in the axial direction, leakage of a fluid such as a refrigerant sucked in by the second impeller 2232 can be prevented.

[0555] For example, when the second impeller 2232 rotates, the plurality of blades 223 b rotate around the hub 223 a , so that the second impeller 2232 can draw refrigerant in the axial direction through the spaces between the plurality of blades 223 b .

[0556] Here, the plurality of sealing protrusions and the second base portion act as flow resistance for the refrigerant flowing through the gap between the first axial sealing portion 236 and the rotating shaft 219 , thereby preventing the refrigerant from leaking through the gap between the inner surface of the first axial sealing portion 236 and the rotating shaft 219 .

[0557] The above-mentioned axial sealing member may also be similarly applied between the first bearing cover 2281 and one side of the rotating shaft 219 .

[0558] (2) Thrust bearing safety device 1

[0559] Fig.16 Yes Fig.13 A conceptual diagram of the thrust bearing safety device 1 is shown with part XVI enlarged.

[0560] Fig.17 It is shown Fig.16 A conceptual diagram of a situation in which an embodiment of the thrust bearing safety device 1 is more specifically implemented.

[0561] Fig.18 It is shown Fig.17 A sectional view of the thrust bearing safety device 1 before operation.

[0562] Fig.19 It is used to illustrate Fig.16 Schematic diagram of the thrust bearing safety device 1 after operation.

[0563] Fig. 20 It specifically shows Fig.19 Schematic diagram of the thrust bearing safety device 1 after operation.

[0564] Fig.21 It specifically shows Fig. 20 A cross-sectional view of the thrust bearing safety device 1 after operation.

[0565] Fig. 22 is along Fig.21 The XXII-XXII line in the figure is cut to illustrate the conceptual diagram of the connection state between the opening and closing valve 238 and the hinge pin 241.

[0566] The suction port of the first impeller housing 211 may be connected to an evaporator or a liquid storage device (or a gas-liquid separator) of a refrigeration cycle device. The suction port of the second impeller housing 2232 may be connected to the discharge port of the first impeller housing 211 .

[0567] The pressure of the refrigerant sucked into the second impeller (or secondary impeller) 2232 is higher than the pressure of the refrigerant sucked into the first impeller 2231 .

[0568] The axial load acting on the other side of the rotating shaft 219 on which the second impeller 2232 is mounted is larger than the axial load acting on the side of the rotating shaft 219 on which the first impeller 2231 is mounted.

[0569] The rotation shaft 219 can move in the axial direction from the first impeller 2231 toward the second impeller 2232 side.

[0570] If the thrust mirror plate 229 moves toward the first bearing cover 2281, the oil film formed in the gap between the first thrust bearing 2271 installed in the first bearing cover 2281 and the thrust mirror plate 229 may be damaged, or the first thrust bearing 2271 may be damaged by applying impact to the first thrust bearing 2271.

[0571] In order to solve such a problem, the bypass flow path 237 is provided.

[0572] The bypass flow path 237 connects the guide vanes 214 a and 214 b of the first impeller casing 211 and the interior of the cover so as to be communicable.

[0573] One side of the bypass flow path 237 is connected to the guide vanes 214a, 214b of the first impeller housing 211, and the other side of the bypass flow path 237 is connected to the first space 217 of the cover. The other side of the bypass flow path 237 can be connected to the gap between the first thrust bearing 2271 and the thrust mirror plate 229.

[0574] The first bearing cover body 2281 may be composed of a first radially extending portion 2281a, a second radially extending portion 2281b and an axially connecting portion 2281c.

[0575] The axial connection portion 2281c may be formed in a cylindrical shape. A first axial hole is formed inside the axial connection portion 2281c so that the rotating shaft 219 passes through.

[0576] The first radially extending portion 2281a may extend radially from one side of the axially connecting portion 2281c to form a disc shape. The second radially extending portion 2281b may extend radially from the other side of the axially connecting portion 2281c to form a disc shape.

[0577] The first radially extending portion 2281a and the second radially extending portion 2281b may be spaced apart from each other in the axial direction.

[0578] The front surface of the first radially extending portion 2281 a is arranged toward the first guide vane 214 a of the first impeller housing 211 , and the back surface of the first radially extending portion 2281 a is arranged toward the second radially extending portion 2281 b .

[0579] The front side of the second radially extending portion 2281 b faces the back side of the first radially extending portion 2281 a , and the back side of the second radially extending portion 2281 b faces the first thrust bearing 2271 or faces the thrust mirror plate 229 .

[0580] The axial connection portion 2281c extends in the axial direction, and connects the first radial extension portion 2281a and the second radial extension portion 2281b in the axial direction. The first radial bearing may be mounted on the inner circumferential surface of the axial connection portion 2281c.

[0581] The bypass flow path 237 may be composed of a first bypass flow path 2371 and a second bypass flow path 2372 .

[0582] The first bypass flow path 2371 is provided in the first radially extending portion 2281a. The first bypass flow path 2371 extends in the axial direction in the first radially extending portion 2281a. The first bypass flow path 2371 is formed to penetrate the first radially extending portion 2281a in the axial direction.

[0583] The second bypass flow path 2372 is provided in the second radially extending portion 2281b. The second bypass flow path 2372 extends in the axial direction in the second radially extending portion 2281b. The second bypass flow path 2372 is formed to penetrate the second radially extending portion 2281b in the axial direction.

[0584] The first bypass flow path 2371 and the second bypass flow path 2372 may be arranged in a straight line along the axial direction.

[0585] One side of the first bypass flow path 2371 may be directly connected to the first guide vane 214a of the first impeller housing 211, or may be indirectly connected to the first guide vane 214a of the first impeller housing 211 through the communication flow path 2373. In this embodiment, a situation is shown in which one side of the first bypass flow path 2371 is connected to the second guide vanes 214a, 214b of the first impeller housing 211 through the communication flow path 2373.

[0586] The communication passage 2373 may be formed axially through the first radial seal portion 230 . One side of the communication passage 2373 may be connected to the first guide vane 214 a of the first impeller housing 211 , and the other side of the communication passage 2373 may be connected to one side of the first bypass passage 2371 .

[0587] In the case where the first radial seal portion 230 is formed integrally with the first bearing housing 2281, the communication flow path 2373 may be omitted. Alternatively, the first bypass flow path 2371 may be further extended to the position where the communication flow path 2373 is originally located.

[0588] The other side of the first bypass flow path 2371 may be connected to communicate with the first space 217 of the housing.

[0589] One side of the second bypass flow path 2372 may be arranged to face the other side of the first bypass flow path 2371 in the axial direction, and may be connected to the first space 217 of the cover body. The other side of the second bypass flow path 2372 may be connected to the first thrust bearing 2271, or may be connected to the gap between the first thrust bearing 2271 and the thrust mirror plate 229.

[0590] According to such a configuration, the bypass flow path 237 connects the first guide vane 214 a and the interior of the cover, and a part of the refrigerant moving toward the first guide vane 214 a can bypass the interior of the cover through the bypass flow path 237 .

[0591] The pressure of the first guide vane 214a decreases, and the internal pressure of the cover increases. In particular, the pressure of the gap between the first thrust bearing 2271 and the thrust mirror plate 229 may increase.

[0592] Thus, the first guide vane 214 a and the interior of the cover body can achieve pressure balance through the bypass flow path 237 .

[0593] In addition, the oil film formed in the gap between the first thrust bearing 2271 and the thrust mirror plate 229 is not damaged, and the gap can be constantly maintained. The oil film performs a lubricating function at the boundary between the thrust bearing 227 and the thrust mirror plate 229.

[0594] In addition, the refrigerant transferred through the bypass flow path 237 may perform a lubrication function between the thrust bearing 227 and the thrust mirror plate 229 .

[0595] Furthermore, the refrigerant transferred through the bypass flow path 237 can reduce the thrust transferred through the thrust mirror plate 229 .

[0596] The on-off valve 238 may be installed on the first guide vane 214a or the first bearing cover 2281. In this embodiment, the on-off valve 238 is installed on the first bearing cover 2281.

[0597] The on-off valve 238 is configured to open and close the bypass flow path 237 .

[0598] The on-off valve 238 may be disposed adjacent to the first bypass flow path 2371 to open and close the first bypass flow path 2371 .

[0599] The on-off valve 238 can move between a first position closing the bypass flow path 237 and a second position opening the bypass flow path 237. The on-off valve 238 can move linearly or rotationally. In this embodiment, the on-off valve 238 is configured to rotate.

[0600] The on-off valve 238 can selectively open and close the bypass flow path 237. For example, the on-off valve 238 can be operated when a high-pressure refrigerant or a liquid refrigerant flows into the guide vanes 214a and 214b and a large axial load is generated.

[0601] The on-off valve 238 can open the bypass flow path 237 when a large axial load is generated, and can close the bypass flow path 237 when the axial loads acting on both ends of the rotating shaft 219 are balanced.

[0602] The on-off valve 238 may be configured to be operated by contact with the thrust mirror plate 229 .

[0603] That is, the on-off valve 238 can use the axial movement of the thrust mirror plate 229 as a power source.

[0604] To this end, the on-off valve 238 includes a valve rod 239 .

[0605] One side of the valve connecting rod 239 may be coupled to one side of the on-off valve 238 , and the other side of the valve connecting rod 239 may be spaced apart from the thrust mirror plate 229 with a gap therebetween so as to be able to contact the front surface of the thrust mirror plate 229 .

[0606] The valve connecting rod 239 may be composed of a connecting rod body 2391 and a valve coupling portion 2392 .

[0607] The connecting rod body 2391 may be formed in a cylindrical shape.

[0608] The valve coupling portion 2392 is formed to protrude from one side of the connecting rod body 2391 toward the on-off valve 238. The valve coupling portion 2392 can be formed in various shapes such as a cylindrical shape or a rectangular parallelepiped shape.

[0609] The diameter of the connecting rod body 2391 is larger than the diameter of the valve coupling portion 2392 .

[0610] Thereby, the area of ​​the connecting rod body 2391 that can contact the thrust mirror plate 229 can be increased.

[0611] The valve coupling portion 2392 may be fastened to one side of the on-off valve 238 via a connecting pin 240 .

[0612] The first bearing cover 2281 includes a valve accommodating portion 242. The valve accommodating portion 242 may be formed to penetrate the first radially extending portion 2281a in the axial direction.

[0613] A valve guide groove 243 is formed at the lower side of the valve accommodation portion 242. The valve guide groove 243 is formed so as to communicate with the space of the valve accommodation portion 242 and the bypass flow path 237.

[0614] The valve guide groove 243 may be formed to correspond to the trajectory of the path along which the on-off valve 238 rotates on the other side.

[0615] Thus, the valve guide groove 243 can prevent interference between the first bearing cover 2281 and the on-off valve 238. The valve guide groove 243 can not only guide the rotation of the on-off valve 238, but also minimize leakage of the refrigerant through the bypass flow path 237.

[0616] The on-off valve 238 may be composed of a valve body 2381 and a flow path opening and closing portion 2382 .

[0617] The valve body 2381 forms the main body of the on-off valve 238. A fastening hole 2383 is formed at one side of the valve body 2381. A connecting pin 240 may be coupled to the fastening hole 2383. The fastening hole 2383 may be formed such that the radial length (direction perpendicular to the axial direction) of the fastening hole 2383 is longer than the axial width of the fastening hole 2383 to allow upstream and downstream clearance of the connecting pin 240.

[0618] The valve body 2381 includes a hinge hole to allow the hinge pin 241 to be fastened.

[0619] One side of the hinge pin 241 can be hingedly coupled to the hinge hole of the valve body 2381 , and the other side of the hinge pin 241 can be fastened to the inner side of the valve accommodating portion 242 of the first bearing cover body 2281 .

[0620] The hinge pin 241 may be provided with a torsion spring 244. The torsion spring 244 may be formed in a spiral coil form. However, elastic members of various structures for returning the on-off valve 238 to the original position may be applied, not limited to the torsion spring 244.

[0621] The torsion spring 244 may be mounted on the hinge pin 241 such that the hinge pin 241 is inserted inside the torsion spring 244 .

[0622] One end of the torsion spring 244 may be fastened to the hinge pin 241 , and the other end of the torsion spring 244 may be fastened to the first bearing cover 2281 .

[0623] According to such a structure, the torsion spring 244 can store elastic force when the opening and closing valve 238 rotates from the closed position to the open position around the hinge pin 241, and then when the axial load acting on the opening and closing valve 238 is released, the elastic force can be used to move the position of the opening and closing valve 238 to the original position (closed position).

[0624] The flow path opening and closing portion 2382 is formed on the other side of the valve body 2381. The flow path opening and closing portion 2382 may be formed in a triangular or conical shape. The flow path opening and closing portion 2382 may be formed in various shapes as long as it can open and close the bypass flow path 237.

[0625] In order to minimize the leakage of the refrigerant, it is preferred that the size and cross-sectional area of ​​the flow path opening and closing portion 2382 be minimized.

[0626] The distance between one end of the opening and closing valve 238 (fastening hole 2383 side) and the hinge pin 241 may be formed to be shorter than the distance between the other end of the opening and closing valve 238 (flow path opening and closing portion 2382 ) and the hinge pin 241 .

[0627] Thus, even if the movement distance (rotation angle) of one end of the on-off valve 238 is small, the movement distance (rotation angle) of the other end (flow path on-off section 2382) of the on-off valve 238 can be increased. Thus, the sensitivity and sensing speed of the on-off valve 238 can be improved.

[0628] The on-off valve 238 is configured to be able to selectively contact the valve rod 239 and the thrust mirror plate 229. The valve rod 239 and the thrust mirror plate 229 are disposed facing each other with a predetermined gap therebetween.

[0629] The gap between the valve connecting rod 239 and the thrust mirror plate 229 can be configured to be smaller than or the same as the gap between the first thrust bearing 2271 and the thrust mirror plate 229. In this embodiment, the situation in which the gap between the valve connecting rod 239 and the thrust mirror plate 229 is configured to be smaller than the gap between the first thrust bearing 2271 and the thrust mirror plate 229 is shown.

[0630] According to such a configuration, when the thrust mirror plate 229 moves axially, the thrust mirror plate 229 first contacts the valve link 239 before contacting the first thrust bearing 2271 .

[0631] The operation start time point of the on-off valve 238 is the same as the contact time point between the valve link 239 and the thrust mirror plate 229 .

[0632] Therefore, when the shaft operates abnormally due to abnormal operation, for example, when high-pressure refrigerant or liquid refrigerant flows into the guide vanes 214a, 214b to generate a large axial load, the on-off valve 238 can quickly respond to the axial load transmitted through the thrust mirror plate 229.

[0633] In addition, the on-off valve 238 does not require an additional detection means for detecting abnormal operation of the rotating shaft 219 , and does not require an electric power source (electric energy) such as a motor for driving the on-off valve 238 .

[0634] In addition, as the axial movement distance of the thrust mirror plate 229 increases, the rotation angle of the on-off valve 238 increases, and the rotation speed becomes faster, so the sensitivity of the on-off valve 238 can be improved.

[0635] (3) Thrust bearing safety device 2

[0636] Fig.23 This is a conceptual diagram for explaining a situation before a thrust bearing safety device 2 according to another embodiment of the present invention is operated.

[0637] Fig.24 It is used to illustrate Fig.23 A conceptual diagram of the thrust bearing safety device 2 after operation.

[0638] With the above Figures 13 to 22 Compared with the embodiment of the present invention, the present embodiment is different in that the magnetic force of the magnet 345 is used to operate the on-off valve 338.

[0639] The on-off valve 338 has a valve connecting rod 339. The valve connecting rod 339 can connect the on-off valve 338 and the thrust mirror plate 229. One side of the valve connecting rod 339 is connected to the on-off valve 338, and the other side of the valve connecting rod 339 is spaced apart from the thrust mirror plate 229 by a predetermined gap.

[0640] The gap between the other end of the valve connecting rod 339 and the thrust mirror plate 229 may be greater than or equal to the gap between the first thrust bearing 2271 and the thrust mirror plate 229. In this embodiment, the situation where the gap between the other end of the valve connecting rod 339 and the thrust mirror plate 229 is the same as the gap between the first thrust bearing 2271 and the thrust mirror plate 229 is shown.

[0641] The first magnet 3451 is mounted on the thrust mirror plate 229. The first magnet 3451 is arranged to be spaced apart from the valve connecting rod 339 in a straight line along the axial direction. A first magnet mounting groove is formed in the thrust mirror plate 229. The first magnet mounting groove can be arranged to face the valve connecting rod 339 along the axial direction.

[0642] One side of the first magnet 3451 may be exposed toward the valve connecting rod 339 to the outside of the thrust mirror plate 229. The exposed one side of the first magnet 3451 may form the same plane as the front side of the thrust mirror plate 229.

[0643] The second magnet 3452 may be installed on the other side of the valve connecting rod 339. The second magnet 3452 is arranged to face the first magnet 3451 in the axial direction. A second magnet installation groove for installing the second magnet 3452 may be formed on the other side of the valve connecting rod 339.

[0644] The second magnet mounting groove may be formed to be open toward the first magnet 3451 .

[0645] One side surface of the second magnet 3452 may be exposed toward the first magnet 3451. The exposed one side surface of the second magnet 3452 may form a same plane as the front end surface of the valve connecting rod 339.

[0646] The first magnet 3451 and the second magnet 3452 are configured to attract each other.

[0647] However, the second magnet 3452 may be selectively applied to the valve connecting rod 339 .

[0648] For example, when the valve connecting rod 339 is formed of a metal material, an attractive force can be formed between the first magnet 3451 and the valve connecting rod 339, so the second magnet 3452 can be omitted. If the valve connecting rod 339 is formed of a non-metallic material that is not affected by magnetic force, the second magnet 3452 can be applied.

[0649] The first magnet 3451 and the second magnet 3452 may be arranged to be spaced apart from each other with a predetermined gap.

[0650] In the neutral position of the thrust mirror plate 229 , the predetermined gap between the first magnet 3451 and the second magnet 3452 is formed to be larger than the distance over which the magnetic force (attractive force) between the magnets 345 can act.

[0651] Here, the neutral position of the thrust mirror plate 229 means that the radial center line of the thrust mirror plate 229 is located at a half (1 / 2) position of the axial distance between the first thrust bearing 2271 and the second thrust bearing 2272 .

[0652] That is, when the distance between the first thrust bearing 2271 and the thrust mirror plate 229 is the same as the distance between the second thrust bearing 2272 and the thrust mirror plate 229 , the thrust mirror plate 229 is located in the neutral position.

[0653] If the separation distance between the first magnet 3451 and the second magnet 3452 is less than or equal to the distance over which the magnetic force between the magnets 345 can act, even if the axial load of the thrust mirror plate 229 does not act in one direction, the on-off valve 338 always works under the action of the gravitational force of the first magnet 3451 and the second magnet 3452, so that the on-off valve 338 can be opened even at normal times.

[0654] The axial load of the thrust mirror plate 229 acting in one direction means that the axial load from the second impeller 2232 toward the first impeller 2231 acts on the thrust mirror plate 229 .

[0655] The distance over which the mutual magnetic force between the first magnet 3451 and the second magnet 3452 can act is smaller than the distance between the first thrust bearing 2271 and the thrust mirror plate 229 .

[0656] The gap between the first magnet 3451 and the second magnet 3452 is larger than the gap between the first thrust bearing 2271 and the thrust mirror plate 229 .

[0657] One side of the on-off valve 338 may be connected to the valve link 339 by means of a connecting pin.

[0658] A flow path opening and closing portion is provided on the other side of the opening and closing valve 338, and can open and close the bypass flow path 237. The other side of the opening and closing valve 338 can be located at a position lower than one side of the opening and closing valve 338.

[0659] The hinge pin may be disposed between one side and the other side of the on-off valve 338 .

[0660] The flow path opening and closing portion of the opening and closing valve 338 may be arranged at a position lower than the hinge pin.

[0661] The operating state of the on-off valve 338 will be described.

[0662] When the high-pressure refrigerant or the liquid refrigerant is sucked into the guide vanes 214 a and 214 b , the rotating shaft 219 may abnormally move in the axial direction toward the first impeller 2231 .

[0663] To cope with this situation, when the thrust mirror plate 229 moves axially, the gap between the first magnet 3451 and the second magnet 3452 can be reduced to a distance within which the magnetic force between the first magnet 3451 and the second magnet 3452 can act.

[0664] At this time, the valve connecting rod 339 moves toward the first magnet 3451 under the action of the attraction between the first magnet 3451 and the second magnet 3452.

[0665] The on-off valve 338 can rotate about the hinge pin to open the bypass flow path 237 .

[0666] A portion of the high-pressure refrigerant or liquid refrigerant flowing into the first guide vane 214 a flows into the interior of the housing through the bypass flow path 237 , thereby achieving pressure balance between the first guide vane 214 a and the interior of the housing.

[0667] The high-pressure refrigerant or the liquid refrigerant flows into the first thrust bearing 2271 along the bypass flow path 237 , and an oil film may be formed between the first thrust bearing 2271 and the thrust mirror plate 229 .

[0668] In addition, the high-pressure refrigerant or the like can offset the axial load of the thrust mirror plate 229 that is biased in one direction.

[0669] As the axial load of the thrust mirror plate 229 is offset, the torsion spring 244 installed on the hinge pin of the on-off valve 338 can overcome the attraction of the magnet 345 through elastic force and return to its original position.

[0670] Other components are the same as above Figures 13 to 22 The embodiments are the same or similar, so repeated description is omitted.

[0671] (4) Thrust bearing safety device 3

[0672] Fig.25 This is a conceptual diagram for explaining a thrust bearing safety device 3 according to still another embodiment of the present invention.

[0673] Fig.26 Yes Fig.25 Part XXVI in FIG. 1 is enlarged to illustrate a conceptual diagram of the working state of the thrust bearing safety device 3 .

[0674] With the above Figures 13 to 24 Compared with the embodiment of the present invention, the present embodiment is different in that a differential pressure valve 446 is used to open and close the bypass flow path 237.

[0675] The differential pressure valve 446 may be provided at the guide vane portion 111b of the first impeller housing 211 or the first bearing cover 2281. In this embodiment, the differential pressure valve 446 is installed at the first bearing cover 2281.

[0676] The differential pressure valve 446 is configured to selectively open and close the bypass flow path 237 .

[0677] The differential pressure valve 446 includes a valve housing 447 , a diaphragm 449 , an opening and closing plunger 450 , and a return spring 451 .

[0678] The valve housing 447 may be formed in a hollow cylindrical shape. A partition plate 449 , a plurality of connecting rods 4541 , 4542 , and an opening and closing plunger 450 may be accommodated inside the valve housing 447 .

[0679] The partition 449 can separate the accommodation space inside the valve housing 447 into a first accommodation portion 4471 and a second accommodation portion 4472. The partition 449 can be configured to slide in the length direction inside the valve housing 447 according to the pressure difference between the first accommodation portion 4471 and the second accommodation portion 4472.

[0680] A first communication port 4481 is formed at one side of the valve cover 447. One side of the first communication port 4481 can be connected to the first guide vane 214a of the first impeller housing 211, and the other side of the first communication port 4481 can be connected to the first accommodation portion 4471 of the valve cover 447.

[0681] According to such a configuration, the high-pressure refrigerant sucked into the first guide vane 214 a can flow into the first accommodation portion 4471 of the valve cover 447 through the first communication port 4481 .

[0682] A second communication port 4482 is formed on the other side of the valve cover 447. One side of the second communication port 4482 can be connected to the second accommodation portion 4472 of the valve cover 447, and the other side of the second communication port 4482 can be connected to the first space 217 of the cover.

[0683] According to such a configuration, the refrigerant flowing into the first space 217 of the cover body can flow into the second accommodation portion 4472 of the valve cover body 447 through the second communication port 4482 .

[0684] The volumes of the first accommodation portion 4471 and the second accommodation portion 4472 may be variable according to the sliding direction of the partition plate 449 .

[0685] The opening and closing plunger 450 may be formed in a cylindrical shape and may be slidably coupled to the valve cover 447 so as to be drawn out of the valve cover 447 or introduced into the first accommodation portion 4471 of the valve cover 447 .

[0686] The opening and closing plunger 450 may be connected to the partition plate 449 by a first connecting rod 4541. The opening and closing plunger may move along the length direction of the valve housing 447 together with the partition plate 449 according to the pressure difference between the first accommodation portion 4471 and the second accommodation portion 4472.

[0687] A spring cover 452 may be provided on the upper portion of the valve cover 447 .

[0688] The restoring spring 451 may be accommodated in the spring cover 452. The pressure plate 453 may be slidably coupled along the length direction of the spring cover 452.

[0689] The return spring 451 may be disposed between the pressure plate 453 and the inner side surface of the spring cover 452 .

[0690] The pressure plate 453 is configured to press the return spring 451 .

[0691] When the pressing force of the pressure plate 453 is released, the restoring spring 451 can use the elastic force to restore the pressure plate 453 to its original position.

[0692] The second connecting rod 4542 extends through the valve cover 447 and the spring cover 452 in the up-down direction. The second connecting rod 4542 can connect the partition plate 449 and the pressure plate 453.

[0693] The pressure plate 453 can move in the up-down direction together with the partition plate 449 .

[0694] Next, the operation state of the differential pressure valve 446 will be described.

[0695] The pressure of the refrigerant sucked into the first guide vane 214a may be greater than the pressure of the refrigerant in the first space 217 of the housing.

[0696] In this case, the pressure of the refrigerant flowing from the first guide vane 214 a into the first accommodating portion 4471 through the first communication port 4481 is higher than the pressure of the refrigerant flowing from the first space 217 of the cover into the second accommodating portion 4472 through the second communication port 4482 .

[0697] The partition plate 449 may rise due to the pressure difference between the first accommodation portion 4471 and the second accommodation portion 4472 .

[0698] The opening and closing plunger 450 rises together with the partition plate 449 to open the bypass flow path 237 .

[0699] The pressure plate 453 rises together with the partition plate 449 to press the return spring 451 .

[0700] The return spring 451 is compressed by the pressing force from the pressure plate 453 .

[0701] The high-pressure refrigerant moves toward the interior of the housing through the bypass flow path 237, so that the pressure between the first guide vane 214a and the interior of the housing can be balanced.

[0702] The refrigerant moving along the bypass flow path 237 may maintain an oil film between the first thrust bearing 2271 and the thrust mirror plate 229 .

[0703] When the liquid refrigerant flows into the first guide vane 214 a , a part of the liquid refrigerant moves to the bypass flow path 237 , so that the inflow amount of the liquid refrigerant sucked into the first guide vane 214 a can be reduced.

[0704] When pressure balance is achieved between the first guide vane 214a and the interior of the cover body, pressure balance can also be achieved between the first accommodation portion 4471 and the second accommodation portion 4472 .

[0705] Therefore, as the pressure difference between the first accommodating portion 4471 and the second accommodating portion 4472 disappears, the pressing force of the pressure plate 453 is also released, and the partition plate 449 drops to its original position under the elastic force of the restoring spring 451.

[0706] The opening and closing plunger 450 can be lowered together with the partition plate 449 to close the bypass flow path 237 .

[0707] Other components are the same as above Figures 13 to 24 The embodiments are the same or similar, so repeated description is omitted.

[0708] (5) Thrust bearing safety device 4

[0709] Fig. 27 This is a conceptual diagram for explaining a thrust bearing safety device 4 according to still another embodiment of the present invention.

[0710] Fig.28 Yes Fig. 27 Part XXVIII in FIG. 1 is enlarged to illustrate a conceptual diagram of the working state of the thrust bearing safety device 4.

[0711] With the above Figures 13 to 26 Compared with the embodiment of the present invention, the present embodiment is different in that a bimetallic valve 555 is used to open and close the bypass flow path 237.

[0712] The bimetal valve 555 may be provided at the guide vane portion 111b of the first impeller housing 211 or the first bearing cover 2281. In this embodiment, the bimetal valve 555 is installed inside the first bearing cover 2281.

[0713] The bimetal valve 555 includes a first bimetal 5551 , a second bimetal 5552 , and a connecting band 5553 .

[0714] The first bimetal 5551 and the second bimetal 5552 are respectively made of metal materials. The first bimetal 5551 and the second bimetal 5552 have different thermal expansion coefficients.

[0715] The first bimetal 5551 has a greater thermal expansion rate than the second bimetal 5552 .

[0716] The first bimetal 5551 may be disposed toward the first guide vane 214a. The second bimetal 5552 may be disposed toward the inner side of the cover. The first bimetal 5551 and the second bimetal 5552 may be disposed overlappingly along the axial direction.

[0717] A plurality of connection strips 5553 may be provided, and the plurality of connection strips 5553 may connect both sides of the first bimetal 5551 and the second bimetal 5552 respectively.

[0718] The connection band 5553 is configured to allow each bimetal 5551, 5552 to thermally expand along the length direction but prevent the bimetal from separating.

[0719] One side of each of the first bimetal 5551 and the second bimetal 5552 may be fixed to the inner side of the first bearing cover 2281. The other side of each of the first bimetal 5551 and the second bimetal 5552 may be configured as a free end.

[0720] The other side of each of the first bimetal 5551 and the second bimetal 5552 is configured to open and close the bypass flow path 237 .

[0721] The bimetal valve 555 may determine whether to operate according to a preset temperature of the refrigerant.

[0722] The working state of the bimetallic valve 555 is described.

[0723] High-temperature and high-pressure refrigerant may be sucked into the first guide vane 214 a .

[0724] The bimetal valve 555 is disposed toward the first guide vane 214 a so as to receive heat from the refrigerant drawn into the first guide vane 214 a .

[0725] Since the thermal expansion coefficient of the first bimetal 5551 is greater than that of the second bimetal 5552 , the expanded length of the first bimetal 5551 is greater than that of the second bimetal 5552 .

[0726] Therefore, the first bimetal 5551 bends toward the second bimetal 5552 .

[0727] Therefore, the bimetallic valve 555 can open the bypass flow path 237 .

[0728] In addition, if the temperature of the refrigerant sucked into the first guide vane 214 a drops below a preset temperature, the bimetallic valve 555 returns to its original position, so that the bypass flow path 237 is closed again.

[0729] Other components are the same as above Figures 13 to 26 The embodiments are the same or similar, so repeated description is omitted.

[0730] (6) Thrust bearing safety device 5

[0731] Fig.29 This is a conceptual diagram for explaining a thrust bearing safety device 5 according to still another embodiment of the present invention.

[0732] With the above Figures 13 to 28 Compared with the embodiment of the present invention, the difference of this embodiment is that the on-off valve 638 is electrically constructed.

[0733] The electric on-off valve 638 of this embodiment can be driven by electric energy. For example, the on-off valve 638 can be driven by receiving power from a driving unit such as a small motor.

[0734] In the above embodiment, a detection means such as a switch 601 may be provided at one end of the valve connecting rod. The switch 601 may output an electrical signal when in contact. The switch 601 may be installed at one end of the valve connecting rod and face the thrust mirror plate 229.

[0735] The detection means may be implemented by a pressure sensor 602. The pressure sensor 602 may be disposed between the thrust mirror plate 229 and the first thrust bearing 2271. The pressure sensor 602 detects the pressure between the thrust mirror plate 229 and the first thrust bearing 2271.

[0736] The controller 603 may receive a detection signal from the switch 601 or the pressure sensor 602 to control the operation of the on-off valve 638 .

[0737] Next, a method for controlling the electric on-off valve 638 will be described.

[0738] The switch 601 detects whether it is in contact with the thrust mirror plate 229 , or the pressure sensor 602 measures the pressure between the thrust mirror plate 229 and the first thrust bearing 2271 .

[0739] If the switch 601 contacts the thrust mirror plate 229 or the measured pressure value is greater than a preset pressure value, the on-off valve 638 starts to operate.

[0740] The controller 603 receives a detection signal from the switch 601 or the pressure sensor 602 to drive the on-off valve 638 .

[0741] The on-off valve 638 can receive power from the valve driving unit to open and close the bypass flow path 237 .

[0742] Other components and Figures 13 to 28 The embodiments are the same or similar, so repeated description is omitted.

[0743] Therefore, according to the present invention, a bypass flow path 237 is formed to connect the guide vanes 214a, 214b of the impeller housing 110 and the interior of the cover body. The bypass flow path 237 bypasses a part of the high-pressure refrigerant or liquid refrigerant flowing toward the compression part (guide vanes 214a, 214b) and transfers it to the interior of the cover body 200.

[0744] Thus, pressure balance is achieved between the guide vanes 214 a and 214 b and the cover body 200 , so that the difference between the axial pressure on the first impeller 2231 side and the axial pressure on the second impeller 2232 side can be minimized.

[0745] In addition, part of the bypassed refrigerant forms an oil film between the thrust bearing 227 and the thrust mirror plate 229. Thus, the bypassed refrigerant plays a role in lubricating the thrust bearing 227, thereby preventing the thrust bearing 227 from being damaged by the axial load applied to the rotating shaft 219.

[0746] When liquid refrigerant flows into the guide vanes 214a and 214b, the bypass flow path 237 bypasses a portion of the liquid refrigerant to flow into the housing 200, thereby minimizing the inflow of liquid refrigerant into the compression portion (guide vanes 214a and 214b).

[0747] Furthermore, the bypass flow path 237 and the on-off valve 238, 338, 638 for opening and closing the bypass flow path 237 are provided inside the guide vanes 214a, 214b or the bearing cover 228, thereby reducing the number of parts, contributing to miniaturization, and reducing manufacturing costs.

[0748] Furthermore, the on-off valves 238 , 338 , and 638 operate by a mechanical mechanism that contacts the thrust mirror plate 229 in accordance with the axial movement of the rotating shaft 219 , thereby simplifying the structure and minimizing the installation space.

[0749] In particular, as a structure in which only the on-off valves 238, 338, 638 and the valve connecting rods 239, 339 are additionally mounted and assembled to the inner side of the bearing cover 228, there is an advantage of easy assembly and disassembly.

[0750] In addition, the bypassed refrigerant moves in the direction opposite to the axial movement direction of the rotating shaft 219, thereby canceling out the axial force. This has the advantage of facilitating alignment between the thrust bearing 227 and the rotating shaft 219 without requiring additional components.

Claims

1. A turbo compressor, wherein: include: Cover body; A rotating shaft, rotatably mounted inside the cover; an impeller coupled to the rotating shaft and rotating; A bearing that rotatably supports the rotating shaft; as well as A bearing cover body, combined with the cover body and supporting the bearing; The bearing comprises: a radial bearing having an air foil bearing mounted on the inner circumferential surface of the bearing housing and surrounding the rotating shaft and arranged with an air gap therebetween to support a radial load of the rotating shaft; and The radial bearing safety device is arranged on the bearing cover body and limits the radial movement distance of the rotating shaft to within the elastic deformation range of the radial bearing.

2. The turbo compressor according to claim 1, wherein: The air foil bearing comprises: a bump foil including a plurality of curved surface portions formed to protrude toward the rotation axis and a connecting portion connecting the plurality of curved surface portions adjacent to each other; and The cover foil is configured to cover the inner side of the bump foil.

3. The turbo compressor according to claim 1, wherein: The radial bearing safety device includes a limiting portion protruding from the inner circumferential surface of the bearing cover toward the rotating shaft.

4. The turbo compressor according to claim 3, wherein: The limiting portion is formed by extending along the inner circumferential surface of the bearing cover body in a circumferential direction.

5. The turbo compressor according to claim 3, wherein: The radial bearing further comprises a wave anti-detachment ring, which is arranged on one side of the air foil bearing to prevent the air foil bearing from detaching in the axial direction; The air foil bearing is arranged between the wave anti-slip ring and the limiting part.

6. The turbo compressor according to claim 5, wherein: The air foil bearing includes a corrugated foil having a curved portion formed to protrude toward the rotating shaft, the corrugated foil having a corrugated height from the inner circumferential surface of the bearing cover toward the radial inside to the vertex of the curved portion; The protruding height of the limiting portion is lower than the wave height, and is higher than the protruding height of the wave anti-slip ring toward the rotating shaft based on the inner circumferential surface of the bearing cover body.

7. The turbo compressor according to claim 3, wherein: The limiting part comprises: A first limiting portion, disposed on one axial side of the radial bearing; and The second limiting portion is arranged on the other axial side of the radial bearing.

8. The turbo compressor according to claim 1, wherein: The air foil bearing includes a corrugated foil having a curved portion formed to protrude toward the rotating shaft, the corrugated foil having a corrugated height from the inner circumferential surface of the bearing cover toward the radial inside to the vertex of the curved portion; The radial bearing safety device includes a limiting portion protruding from the inner circumferential surface of the bearing cover toward the rotating shaft, and the protruding height of the limiting portion is lower than the wave height.

9. The turbo compressor according to claim 8, wherein: The protruding height of the limiting portion is 40-50% of the wave height.

10. The turbo compressor according to claim 3, wherein: The limiting portion has an outer surface formed with a wear-resistant coating.

11. The turbo compressor according to claim 1, wherein: The radial bearing safety device comprises: A ring mounting groove is formed by being recessed along the circumferential direction on the inner circumferential surface of the bearing housing; and The limiting ring extends in the circumferential direction to surround the rotating shaft and be separated from the rotating shaft by an air gap, and the limiting ring is installed in the ring installation groove.

12. The turbo compressor according to claim 11, wherein: The limiting ring comprises: A first limiting ring, arranged on one axial side of the radial bearing; and The second limiting ring is arranged on the other axial side of the radial bearing.

13. The turbo compressor according to claim 1, wherein: The radial bearing safety device comprises: A plurality of ball receiving grooves are formed concavely on the inner peripheral surface of the bearing cover; and A plurality of ball bearings are arranged circumferentially spaced apart from the rotating shaft with an air gap therebetween, and are mounted in the ball receiving groove.

14. The turbo compressor according to claim 1, wherein: The radial bearing safety device comprises: A plurality of needle roller receiving grooves are formed concavely on the inner peripheral surface of the bearing cover; and The needle roller bearing is arranged to be spaced apart from the rotating shaft in the circumferential direction with an air gap therebetween, and is installed in the needle roller receiving groove.

15. The turbo compressor according to claim 1, wherein: Also included is a thrust mirror plate protruding radially from the rotating shaft; The bearing further includes a thrust bearing having an air foil bearing which is arranged with an air gap apart from the thrust mirror plate to support the axial load of the rotating shaft.

16. The turbo compressor according to claim 1, wherein: Also includes: an impeller housing accommodating the impeller and having a guide vane extending in a spiral shape from one side of the impeller and compressing the refrigerant sucked by the impeller; as well as A bypass flow path is formed between the interior of the guide vane and the interior of the cover so that a part of the refrigerant flowing into the guide vane bypasses the interior of the cover.

17. The turbo compressor according to claim 16, wherein: The bearing includes a thrust bearing supporting the axial load of the rotating shaft; One side of the bypass flow path is communicated with the guide vane, and the other side of the bypass flow path is communicated with the thrust bearing.

18. The turbo compressor according to claim 16, wherein: The bypass flow path is formed to penetrate the bearing cover, one side of the bypass flow path is communicated with the guide vane, and the other side of the bypass flow path is communicated with the interior of the cover.

19. The turbo compressor according to claim 16, wherein: The bearing housing comprises: an axial connection portion formed to surround the rotating shaft; A first radially extending portion extending radially from one side of the axial connecting portion; and A second radially extending portion extending radially from the other side of the axial connecting portion; The bypass flow path is formed to penetrate the first radially extending portion.

20. The turbo compressor according to claim 19, wherein: The bypass flow path comprises: A first bypass flow path is formed through the first radially extending portion in one direction; and A second bypass flow path is formed penetrating the second radially extending portion along the one direction.

21. The turbo compressor according to claim 20, wherein: A diameter of the second bypass flow path is greater than or equal to a diameter of the first bypass flow path.

22. The turbo compressor according to claim 16, wherein: An on-off valve is included which is provided at one side of the bypass flow path and opens and closes the bypass flow path.

23. The turbo compressor according to claim 22, wherein: It includes a valve connecting rod, one side of which is connected to the opening and closing valve, and the other side is configured to be contactable and separated from the rotating shaft. When the rotating shaft moves axially, the valve connecting rod contacts the rotating shaft and transmits the power of the axial movement of the rotating shaft to the opening and closing valve.

24. The turbo compressor according to claim 23, wherein: include: A thrust mirror plate extending radially from the rotation axis; as well as A thrust bearing is arranged at a gap between the bearing housing and the thrust mirror plate, and has a corrugated foil and a cover foil covering the corrugated foil to support the axial load of the rotating shaft; The gap between the valve connecting rod and the thrust mirror plate is smaller than or equal to the gap between the thrust bearing and the thrust mirror plate.

25. The turbo compressor according to claim 16, wherein: include: A thrust mirror plate extending radially from the rotation axis; as well as An on-off valve configured to be able to open and close the bypass flow path; The on-off valve comprises: A valve body having a flow path opening and closing portion formed at one end for opening and closing the bypass flow path; a valve connecting rod rotatably coupled to the other end of the valve body, wherein when the thrust mirror plate moves axially, the valve connecting rod contacts the thrust mirror plate and transmits the axial movement power of the thrust mirror plate to the other end of the valve body; and The hinge pin is hingedly connected between one end and the other end of the valve body, and plays the role of a central axis for the rotation of the valve body.

26. The turbo compressor according to claim 25, wherein: Also included is an elastic member mounted on the hinge pin to return the valve body to its original position; The elastic member is a torsion spring having one side coupled to the bearing cover and the other side coupled to the rotating shaft.

27. The turbo compressor according to claim 16, wherein: include: A thrust mirror plate extending radially from the rotation axis; An on-off valve is provided to be able to open and close the bypass flow path formed inside the bearing cover; a valve connecting rod, one side of which is coupled to the on-off valve, and the other side of which is spaced apart from the thrust mirror plate so as to be selectively contactable; and magnets, respectively mounted on the end of the valve connecting rod and the thrust mirror plate facing the end of the valve connecting rod, so as to selectively move the valve connecting rod; The on-off valve is opened and closed by the magnetic force of the magnet.

28. The turbo compressor according to claim 16, wherein: comprising an on-off valve, the on-off valve being configured to be able to open and close the bypass flow path formed inside the guide vane or the bearing cover; The on-off valve is a differential pressure valve that operates by the pressure difference between the guide vane and the inside of the cover.

29. The turbo compressor according to claim 16, wherein: comprising an on-off valve, the on-off valve being configured to be able to open and close the bypass flow path formed inside the guide vane or the bearing cover; The on-off valve is a bimetal valve that operates according to the temperature of the refrigerant sucked into the guide vane.

30. A turbo compressor according to any one of claims 16 to 29, wherein: The impeller comprises: A first impeller rotatably coupled to one end of the rotating shaft; and A second impeller rotatably coupled to the other end of the rotating shaft; The guide vane comprises: a first guide vane compressing a working fluid sucked through the first impeller; and a second guide vane to re-compress the compressed working fluid sucked from the first guide vane through the second impeller; One side of the bypass flow path is communicated with the first guide vane, and the other side of the bypass flow path is communicated with the interior of the cover body.

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