KR20230172887A - Turbo compressor - Google Patents

Abstract

A turbo compressor is started. The turbocompressor includes a housing, rotating shaft, impeller, thrust runner and thrust bearing. The thrust bearing supports the axial load generated on the thrust runner when the pressure of the working fluid increases by the impeller. The thrust runner includes: a first surface disposed toward an axial direction where the axial load acts; a second surface disposed facing in an opposite direction to the first surface; and a flow path forming groove that is recessed in the axial direction on the second surface and forms a flow path through which the cooling fluid inside the housing flows.

Description

Turbo compressor{TURBO COMPRESSOR}

The present invention relates to a turbocompressor equipped with a thrust bearing safety device.

In general, a compressor is widely used in home appliances and throughout the industry, and is a device that compresses air, refrigerant, or various other operating gases by receiving power from a power generator such as an electric motor or turbine.

The compressor includes a turbo compressor. A turbo compressor rotates a blade wheel (hereinafter referred to as an impeller) at high speed to apply centrifugal force, converting part of the speed energy into pressure energy and compressing the working gas.

For example, a turbo compressor may be used in a chiller system that supplies cold water to a demand point. The chiller system cools cold water by heat exchange between the refrigerant circulating in the refrigerant cycle and the cold water circulating in the demand source.

Korean Patent Publication No. 10-2013-0095770 (hereinafter referred to as Patent Document 1) discloses an exhaust gas turbocharger having a means for axially fixing the shaft in case of compressor wheel rupture.

Patent Document 1 is an invention regarding a retaining ring that fixes the rotating shaft in the axial direction when the compressor turbine and impeller are damaged.

According to the invention in Patent Document 1, when the compressor turbine and impeller are damaged, parts may be broken and scattered outside the housing, and to solve the problem of difficulty in disassembling, the retaining ring fixes the shaft in the axial direction when the impeller and turbine are damaged. , It is a structure that prevents the shaft from coming off and makes disassembly and assembly easy.

However, Patent Document 1 is not a device for preventing damage to impellers, etc., but a device for improving damage after damage. Therefore, a device that can prevent damage to components is needed.

Korean Patent Publication No. 10-2001-0064028 (hereinafter referred to as Patent Document 2) discloses a safety device for a turbo compressor.

Patent Document 2 is an invention regarding a safety device that detects the temperature of the bearing using a temperature sensor and cuts off the power to the system when the temperature of the bearing rises above a preset temperature.

However, Patent Document 2 has the disadvantage that it is difficult to respond in real time during high-speed operation and the system is complicated.

Korean Patent Publication No. 10-2014-0129407 (hereinafter referred to as Patent Document 3) discloses a motor cooling device for an air compressor.

Patent Document 3 configures the rotating shaft as a hollow shaft and uses the hollow shaft as an internal passage to recirculate cooling air to the front of the compressor through the internal passage, thereby not only securing stability against surges, but also establishing a recirculation path for air outside the motor. Since it is formed inside the motor rather than in the area, it has the advantage of a simple structure.

However, Patent Document 3 has a structure that cannot be used in a two-stage compressor, and because the discharge air from the impeller is recirculated along the internal flow path, there is a problem in that compression efficiency is reduced due to air leakage.

Additionally, because the discharge air is compressed air and has a relatively high temperature, there is a problem in that cooling performance is lowered.

Korean Patent No. 10-1847165 (hereinafter referred to as Patent Document 4) discloses a cooling passage structure of a turbo blower equipped with an airfoil bearing.

According to Patent Document 4, a turbo blower equipped with an airfoil bearing can evenly cool the airfoil bearings, the stator of the motor, the rotor, and the motor housing, improve cooling performance, and prevent damage to each bearing. Because debris does not move to the remaining bearings, damage to the bearings and rotor shaft can be prevented.

However, since Patent Document 4 uses a separate core fan, it has the disadvantage of increasing the number of parts and requiring additional consideration of the stability of rotordynamics.

In addition, there is a disadvantage in that the structure is complicated because a plurality of internal flow paths and external pipes are formed for each area to be cooled.

In addition, since external piping is used, there is a disadvantage in that the compressor becomes larger and the number of parts increases.

The first object of the present invention is to provide a turbo compressor that can prevent damage to components such as bearings by reducing axial load.

The second object of the present invention is to provide a turbo compressor that can quickly cool the heat of the bearing in real time during high-speed operation and has a simple structure.

The third object of the present invention is to provide a cooling structure applicable to a two-stage compressor, and to cool bearings, etc. without forming a recirculation passage that causes air leakage from the impeller, thereby preventing a decrease in compression efficiency due to air leakage. The goal is to provide turbo compressors.

The fourth object of the present invention is to provide a turbo compressor that can contribute to miniaturization of the compressor without the need to additionally consider the reduction of the number of parts and the stability of rotor dynamics.

As a result of the present inventor's intensive research, the problems of the present invention and the first to sixth objectives described above can be achieved by the following embodiments of the present invention.

(One) A turbo compressor according to an embodiment of the present invention includes a housing; a rotating shaft rotatably mounted inside the housing; an impeller coupled to the rotating shaft and rotating; A thrust runner formed to protrude in a radial direction from the rotation axis; and a thrust bearing that supports an axial load generated on the thrust runner when the pressure of the working fluid increases by the impeller, wherein the thrust runner has a first surface disposed toward the axial direction where the axial load acts. ; a second surface disposed facing in an opposite direction to the first surface; and a flow path forming groove that is recessed in the axial direction on the second surface and forms a flow path through which the cooling fluid inside the housing flows.

According to this configuration, the flow path forming groove generates a flow of cooling fluid when the rotating shaft rotates, and the cooling fluid flowing into the flow path forming groove cools the first surface of the thrust runner, which is the high temperature side, through heat conduction of the thrust runner. By doing so, damage to parts due to deterioration of the thrust bearing can be prevented in advance.

(2) In the above (1), the thrust bearing includes: a first thrust bearing disposed to face the first surface; It includes a second thrust bearing disposed to face the second surface and non-overlapping in the axial direction with the flow path forming groove.

According to this configuration, the inside of the second thrust bearing can be reduced to minimize flow resistance when cooling fluid flows into the flow path forming groove.

(3) In (1), the first surface may be formed as a flat surface, and the second surface may be formed as a curved surface.

According to this configuration, when the thrust runner rotates, the flow rate of the cooling fluid rotating along the second surface is faster than the flow rate of the cooling fluid rotating along the first surface, so that the flow rate of the cooling fluid rotating along the first surface is increased from the first surface to the second surface. By generating a force in the opposite direction of the thrust, the axial load that occurs when the pressure of the working fluid increases by the first and second stage impellers can be reduced.

(4) In (1), the flow path forming groove may be formed on the radial inner side of the thrust runner.

According to this configuration, when the left and right ends of the rotation axis rotate in the vertical direction based on the vertical center line of the thrust runner, the outer end of the thrust runner touches the outer end of the thrust bearing first, so that the second axial load does not act. A portion of the inner side of the thrust bearing is reduced, but the flow path forming groove is formed on the inner side of the thrust runner that does not overlap the second thrust bearing, which is advantageous in terms of support for the axial load and moment of the thrust runner.

(5) In (1), the flow path forming groove is formed as a curved surface with a preset curvature, and the depression depth of the flow path forming groove may increase from the radial inner side to the outer side of the thrust runner.

According to this configuration, the depression depth of the flow path forming groove is inversely proportional to the thickness of the thrust runner, and if the depth of the flow path forming groove increases, it is disadvantageous in terms of the rigidity of the thrust runner, but the thrust with the deepest depth of the flow path forming groove Heat conduction occurs through parts of the runner, improving cooling performance.

(6) In (1), the first corner portion connecting the first surface and the rotation shaft, and the second corner portion connecting the flow path forming groove and the rotation shaft are each formed as curved surfaces having different curvatures, and The radius of curvature of the second corner portion may be larger than the radius of curvature of the first corner portion.

According to this configuration, the second corner portion can minimize flow resistance when the flow direction of the cooling fluid changes from the rotation axis to the second surface of the thrust runner as the radius of curvature increases or decreases.

(7) In (6), the first corner portion connecting the first surface and the rotating shaft, and the second corner portion connecting the flow path forming groove and the rotating shaft each have different axial thicknesses, and the second corner portion has different axial thicknesses. The axial thickness of the portion may be greater than the axial thickness of the first corner portion.

According to this configuration, the thickness of the second corner portion becomes thicker than the thickness of the first corner portion, thereby reinforcing the decrease in rigidity of the flow path forming groove.

(8) In (1), the thrust bearing includes: a first thrust bearing disposed to face the first surface; and a second thrust bearing facing the radial outer side of the second surface and disposed to non-overlap in the axial direction with the flow path forming groove formed on the radial inner side of the second surface, wherein the second thrust bearing is disposed in a radial direction on the inner peripheral surface of the housing. a partition formed to protrude inward and on which the second thrust bearing is mounted; And it may further include a cooling passage provided between the radially inner end of the partition and the rotation shaft, and disposed to overlap in the axial direction with the passage forming groove.

According to this configuration, as the size of the second thrust bearing is reduced, the radial inner length of the partition can be reduced, and a cooling passage is formed inside the reduced partition, thereby further improving the movement path of the cooling fluid through the cooling passage. It can be secured widely.

(9) In (1), the thrust bearing includes: a first thrust bearing disposed to face the first surface; and a second thrust bearing facing the radial outer side of the second surface and disposed to non-overlap in the axial direction with the flow path forming groove formed on the radial inner side of the second surface, wherein the second thrust bearing is disposed in a radial direction on the inner peripheral surface of the housing. a partition formed to protrude inward and on which the second thrust bearing is mounted; And it may further include a cooling passage formed to penetrate the radial inner side of the partition in the axial direction and disposed to overlap the passage forming groove in the axial direction.

According to this configuration, the cooling passage is formed to penetrate in the axial direction without reducing the length of the radial inner end of the partition, thereby securing a movement path for the cooling fluid.

(10) A turbo compressor according to another embodiment of the present invention includes a housing; a rotating shaft rotatably mounted inside the housing; an impeller coupled to the rotating shaft and rotating; a thrust runner that protrudes radially from the rotation axis and has first and second surfaces facing opposite directions in the axial direction; a first thrust bearing disposed to face the first surface on which an axial load acts when the pressure of the working fluid is increased by the impeller and supporting the axial load; a second thrust bearing disposed to face the second surface on which the axial load does not act; and a cooling fan provided on the radial inner side of the second surface and disposed to non-overlap in the axial direction with the second thrust bearing.

According to this configuration, the cooling fan is formed integrally with the rotating shaft and sucks the cooling fluid inside the housing into the inside of the second surface of the thrust runner, which not only increases the fluidity of the cooling fluid even in a narrow space, but also removes the cooling fluid from the high temperature side. 1By supplying cooling fluid to the gap between the thrust bearing and the first surface of the thrust runner, it is possible to respond to the heat of the bearing in real time. Additionally, the cooling fan can generate a force in the direction opposite to the thrust by generating a pressure difference according to the difference in flow rate between the first and second surfaces of the thrust runner.

(11) In (10), the cooling fan includes a protrusion receiving groove formed to be recessed in the axial direction on the second surface and extending in the circumferential direction; And it may include a plurality of rotating protrusions that are formed to protrude in the axial direction from the protrusion-receiving groove and are spaced apart in the circumferential direction of the protrusion-receiving groove.

According to this configuration, the plurality of rotating protrusions can increase responsiveness for the rotating flow of cooling fluid.

(12) In (11), the rotating protrusion may extend in a semicircular shape between the inner and outer sides of the protrusion receiving groove.

According to this configuration, the rotating protrusion is formed in a semicircular shape, so that the cooling fluid adjacent to the second surface can be easily rotated when the thrust runner rotates.

(13) In (10), the cooling fan includes a blade receiving groove formed to be recessed in the axial direction on the second surface and extending along the circumferential direction; a first blade portion formed between the inner and outer sides of the blade receiving groove and inclined at a preset angle with respect to the radial direction; And it may include a second blade portion extending in the circumferential direction from the outer end of the first blade portion.

According to this configuration, the blade portion is bent in a “V” shape, thereby increasing the power for rotation of the cooling fluid.

(14) In (10), the cooling fan includes: a blade receiving portion formed to be axially recessed in the second surface and extending along a circumferential direction; and a plurality of blade protrusions extending obliquely at a preset angle with respect to the radial direction or extending at a preset curvature between the inner and outer sides of the blade receiving portion.

According to this configuration, the structure of the cooling fan can be simplified.

(15) In (10), the cooling fan includes a plurality of rotating ribs formed to protrude in the axial direction from the second surface and extending along the radial direction; a plurality of flow path forming grooves formed to be recessed in the axial direction on the second surface and formed between the plurality of rotating ribs adjacent to each other in the circumferential direction; And it may include a circular rib extending circularly to connect outer ends of the plurality of rotating ribs.

According to this configuration, the plurality of rotating ribs are arranged at equal intervals in the circumferential direction, so that cooling performance can be improved by uniformly distributing the cooling fluid to the flow path forming grooves.

(16) In (10), a plurality of spiral protrusions are formed to protrude in the axial direction from the second surface and extend helically; and a plurality of spiral grooves that are recessed in the axial direction on the second surface and are formed between the plurality of spiral protrusions adjacent to each other in the circumferential direction.

According to this configuration, the spiral protrusion has the advantage of efficiently rotating the cooling fluid and having a simple structure.

(17) In any one of (1) to (16) above, an electric motor connected to the rotation shaft to rotate the impeller; and an impeller casing that accommodates the impeller and has a diffuser that extends spirally from one side of the impeller to compress the refrigerant sucked by the impeller, wherein the impeller is rotatably coupled to one end of the rotating shaft. First impeller; and a second impeller rotatably coupled to the other end of the rotating shaft, wherein the diffuser includes: a first diffuser that compresses the working fluid sucked through the first impeller; and a second diffuser for recompressing the compressed working fluid sucked from the first diffuser through the second impeller, wherein the thrust bearing supports the axial load from the second impeller toward the first impeller. can do.

According to this configuration, the flow path forming groove of the present invention can be applied to a two-stage turbo compressor in which the first and second stage impellers are respectively coupled to both ends of the rotating shaft, and is also effective in preventing leakage of the working fluid while moving from the impeller to the diffuser. .

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

First, in the process of compressing the working fluid by the first and second stage impellers, a unilateral axial load occurs on the rotating shaft. To support the axial load, a thrust runner is formed to protrude in the radial direction from the rotation axis. Unilateral axial load occurs in a two-stage impeller. It acts in the axial direction toward the first stage impeller.

The thrust bearing may be composed of a first thrust bearing disposed to face the first surface of the thrust runner and a second thrust bearing disposed to face the second surface of the thrust runner.

The first surface of the thrust runner is disposed toward the first-stage impeller, and an axial load acts on the first surface. The second surface of the thrust runner is disposed toward the second-stage impeller, and no axial load acts on the second surface.

Axial load, or thrust, is related to the area of the thrust bearing. Additionally, when the left and right ends of the rotation axis rotate based on the vertical center line of the thrust runner, the outer end of the thrust runner first touches the outside of the thrust bearing.

Therefore, the area of the second thrust bearing on which the axial load does not act is reduced, but the inner end of the second thrust bearing is not in contact when supporting the axial load and rotating, so the inner end of the second thrust bearing can be deleted. .

When the inner part of the second thrust bearing is reduced, the part from which the second thrust bearing has been removed can be used as a cooling passage, and a wide cooling passage can be secured even in the narrow internal space of the housing.

Second, a flow path forming groove may be formed on the second surface of the thrust runner. The flow path forming groove can smoothly introduce cooling fluid into the gap between the thrust runner and the second thrust bearing. The cooling fluid flowing into the flow path forming groove can cool the first surface of the thrust runner and the first thrust bearing, which generate high temperature heat when the rotating shaft rotates at high speed, through heat conduction. Therefore, damage to components due to deterioration of the thrust bearing can be prevented.

Third, when the rotating shaft rotates at high speed, the rotational speed of the fluid in the gap between the thrust runner and the thrust bearing increases, making it possible to respond in real time to the temperature increase of the thrust bearing.

Fourth, the second thrust bearing of the present invention has a reduced diameter compared to the first thrust bearing, and the first and second thrust bearings facing the first and second surfaces of the thrust runner, respectively, have an asymmetric structure. A flow path forming groove is formed on the second surface of the thrust runner, and the second surface is a curved surface. On the other hand, the first side of the thrust runner is flat. Because of this, the flow rate of the cooling fluid flowing along the second side of the thrust runner is faster than the flow rate of the cooling fluid flowing along the first side of the thrust runner.

Therefore, the thrust runner can reduce the thrust (axial load) by generating a force in the opposite direction of the thrust from the first surface to the second surface as a difference in flow velocity occurs between the first and second surfaces. .

Fifth, the thrust runner of the present invention has a cooling fan on the inside of the second surface, so that the cooling fluid inside the housing can flow more actively and the cooling fluid can be sucked into the thrust runner and thrust bearing.

As the rotational speed of the rotating shaft increases, the suction power of the cooling fan increases, thereby improving the cooling performance of the cooling fan.

Additionally, the cooling fan can significantly contribute to reducing the axial load by increasing the pressure difference between the second surface and the first surface of the thrust runner.

Sixth, the flow path forming groove and cooling fan of the present invention can be applied to a two-stage turbo compressor in which a first-stage impeller and a second-stage impeller are coupled to both ends of the rotating shaft, so that a part of the working fluid sucked through the impeller is transferred to the inside of the housing. Since there is no need to circulate, leakage of the working fluid can be prevented.

Seventh, the cooling fan of the present invention is formed integrally with the thrust runner in the form of protrusions or grooves, so cooling performance can be improved without using a separate core fan. In addition, the number of parts can be minimized, and there is no need to additionally consider the stability of rotor dynamics. In addition, the simplification of the structure can greatly contribute to the miniaturization of the compressor.

1 is a cross-sectional view for explaining the configuration of a turbo compressor according to the present invention.
Figure 2 is an exploded view of the turbo compressor in Figure 1.
Figure 3 is a conceptual diagram showing impellers mounted on both ends of the rotating shaft in Figure 1, respectively.
Figure 4 is a conceptual diagram showing the left and right ends of the rotation axis rotating around the thrust runner in Figure 3.
FIG. 5 is a conceptual diagram showing the inside of the second thrust bearing in FIG. 1 reduced.
FIG. 6 is a conceptual diagram showing a cooling passage added to the inner end of the bulkhead where the second thrust bearing is mounted in FIG. 5.
FIG. 7 is a conceptual diagram showing the cooling passage expanded by removing the inside of the bulkhead in FIG. 5 where the second thrust bearing is not installed.
FIG. 8 is a conceptual diagram showing a flow path forming groove formed on the non-operating surface of the bearing of the thrust runner in FIG. 3.
Figure 9 is a graph showing thrust runner stress according to the second radius of curvature (R2) of the second corner of the thrust runner.
Figure 10 is a graph showing thrust runner stress according to thrust runner thickness.
Figure 11 is a conceptual diagram showing a cooling fan installed in a thrust runner according to an embodiment of the present invention.
Figure 12 is a conceptual diagram showing a cooling fan installed in a thrust runner according to another embodiment of the present invention.
Figure 13 is a conceptual diagram showing a cooling fan installed in a thrust runner according to another embodiment of the present invention.
Figure 14 is a conceptual diagram showing a cooling fan installed in a thrust runner according to another embodiment of the present invention.
Figure 15 is a conceptual diagram showing a cooling fan installed in a thrust runner according to another embodiment of the present invention.

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

In the following description, in order to clarify the characteristics of the present invention, descriptions of some components may be omitted.

1. Definition of terms

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be.

On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise.

“Axial direction” used in the following description means the axial direction of the rotation axis.

“Radial direction” used in the following description refers to the radial direction of the rotation axis.

Stress used in the following description refers to the resistance force generated inside the material when an external force acts on the material. Stress refers to the force acting per unit area.

Curvature used in the following description refers to the degree of bending of the curve. The radius of curvature is the reciprocal of curvature and means the radius of the arc closest to the curve.

2. Description of the configuration of a turbo compressor according to an embodiment of the present invention

Hereinafter, each configuration of a turbo compressor according to an embodiment of the present invention will be described with reference to the attached drawings.

1 is a cross-sectional view for explaining the configuration of a turbo compressor according to the present invention.

Figure 2 is an exploded view of the turbo compressor in Figure 1.

FIG. 3 is a conceptual diagram showing the impellers 123 mounted on both ends of the rotating shaft 119 in FIG. 1, respectively.

The turbo compressor according to the present invention includes a housing 100, a transmission unit 120, a rotating shaft 119, an impeller 123, an impeller casing (111, 112), a bearing housing 128, a thrust bearing 127, and a journal bearing. Includes (124).

(One) Components of a Compressor

The housing 100 may be formed in a cylindrical shape. The housing 100 may form the appearance of a turbo compressor.

Both sides of the housing 100 may be fastened to the impeller casings 111 and 112.

A receiving 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 partitioned by a partition wall 116.

The partition wall 116 may be formed to protrude in a radial direction from the inner peripheral surface of the housing 100 toward the rotation axis 119. The partition wall 116 may extend in the circumferential direction along the inner peripheral surface of the housing 100. The partition wall 116 may be formed in the shape of a disk having a preset thickness.

An axis penetration hole may be formed in the central portion of the partition wall 116 to allow the rotation axis 119 to penetrate therethrough.

The partition wall 116 is arranged to be spaced apart from the rotation axis 119 at a preset distance in the radial direction.

The partition wall 116 may be disposed skewed in one direction from the longitudinal center of the housing 100.

The first space 117 may be open toward one side of the housing 100, and the second space 118 may be open toward the other side of the housing 100.

The volumes of the first space 117 and the second space 118 may be different. The volume of the first space 117 may be smaller than the volume of the second space 118.

The electric motor 120, which will be described later, can be accommodated in the second space 118, which has a relatively large volume. A portion of the first bearing housing 1281, which will be described later, may be accommodated in the first space 117. A second bearing housing 1282, which will be described later, can be accommodated in the second space 118.

The rotation axis 119 may be arranged horizontally in the first space 117 and the second space 118 so as to axially cross the radial center of the housing 100.

The transmission unit 120 includes a stator 121 and a rotor 122. The stator 121 includes a stator core 1211 and a stator coil 1212. The stator core 1211 may be formed into a cylindrical shape by laminating and combining a plurality of electrical steel plates.

The stator core 1211 may be formed with a plurality of teeth protruding radially toward the rotation axis 119 on the inside of the stator core 1211. A plurality of slots may be formed between the plurality of teeth. A plurality of teeth and a plurality of slots may be alternately arranged in the circumferential direction of the stator core 1211 and spaced apart in the circumferential direction.

The stator coil 1212 is wound on the stator core 1211 through a slot.

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

The rotor 122 is disposed inside the stator 121. The rotor 122 is arranged to be spaced apart from the stator 121 with an air gap. The rotor 122 is mounted on the rotation shaft 119 to be rotatable with respect to the stator 121.

The rotor 122 may include a rotor core and a permanent magnet 1221. The rotor core may be mounted rotatably with the rotation shaft 119 or may be omitted. When the rotor core is omitted, the permanent magnet 1221 can be mounted on the rotating shaft 119.

The permanent magnet 1221 is arranged to overlap the stator in the radial direction. The permanent magnet 1221 may be mounted on the rotating shaft 119 or the rotor core. Alternatively, the permanent magnet 1221 may be accommodated inside the sleeve 1222 and coupled between the first shaft portion 1191 and the second shaft portion 1192 of the rotation shaft 119. In this embodiment, the permanent magnet 1221 is accommodated inside the sleeve 1222 and is shown coupled between the first and second shaft portions 1191 and 1192 of the rotating shaft 119.

The rotation shaft 119 may include a first shaft portion 1191, a second shaft portion 1192, and a sleeve 1222. A first impeller 1231, which will be described later, may be mounted on one end of the first shaft portion 1191. A thrust runner 129, which will be described later, may be formed to protrude in the radial direction on one side of the outer peripheral surface of the first shaft portion 1191.

A second impeller 1232, which will be described later, may be mounted on the other end of the second shaft portion 1192. The first shaft portion 1191 and the second shaft portion 1192 may be arranged to be spaced apart in the axial direction.

The sleeve 1222 is formed in the shape of a hollow cylinder. The sleeve 1222 is disposed between the first shaft portion 1191 and the second shaft portion 1192 and connects the first shaft portion 1191 and the second shaft portion 1192.

The sleeve 1222 is coupled to receive the other end of the first shaft portion 1191 and one end of the second shaft portion 1192. The permanent magnet 1221 may be press-fitted to the inner peripheral surface of the sleeve 1222.

The axial movement of the sleeve 1222 may be restricted by a plurality of protruding protrusions in the radial direction from the rotation axis 119.

The permanent magnet 1221 is formed in a cylindrical shape.

According to this configuration, when power is applied to the stator 121, the rotor 122 can rotate with respect to the stator 121 due to electromagnetic interaction between the stator 121 and the rotor 122.

The rotation shaft 119 rotates together with the rotor 122 and transmits rotational force to the impeller 123, which will be described later.

The rotating shaft 119 may be supported at both ends by bearings. The bearing includes a first bearing and a second bearing.

The first bearing is configured to support one side of the rotation shaft 119. The first bearing may be disposed between the transmission unit 120 and the first stage impeller 123, which will be described later. The first-stage impeller 123 may be named the first impeller 1231.

The second bearing is configured to support the other side of the rotating shaft 119. The second bearing may be disposed between the transmission unit 120 and the second-stage impeller 123, which will be described later. The second-stage impeller 123 may be named the second impeller 1232.

The bearing may include a journal bearing 124 supporting the radial load of the rotating shaft 119 and a thrust bearing 127 supporting the axial load of the rotating shaft 119.

The first bearing may include a first journal bearing 1241, a first thrust bearing 1271, and a second thrust bearing 1272.

The second bearing may include a second journal bearing 1242.

The bearing housing 128 includes a first bearing housing 1281 and a second bearing housing 1282.

The first bearing housing 1281 is configured to support the first bearing. However, the second thrust bearing 1272 may be supported on the partition wall 116.

The first bearing housing 1281 may be formed in a cylindrical shape. The first bearing housing 1281 may have a circular pocket portion formed on the inside in the radial direction.

The first bearing housing 1281 may be disposed between the first impeller casing 111, which will be described later, and the partition wall 116 of the housing 100. A portion of the first bearing housing 1281 may be accommodated in the first space 117 of the housing 100, and another portion of the first bearing housing 1281 may be accommodated inside the first impeller casing 111. .

The first bearing housing 1281 may be press-fitted to the inside of the first impeller casing 111.

A first shaft hole is formed inside the first bearing housing 1281 so that the rotation axis 119 passes through it. The first shaft hole is formed larger than the diameter of the rotation axis 119.

The first bearing may be mounted on the first bearing housing 1281.

The first journal bearing 1241 may be mounted to be accommodated inside the radial direction of the first bearing housing 1281.

The second bearing housing 1282 may include a bearing receiving portion and a radial extension portion.

A cylindrical second shaft hole is provided inside the bearing receiving portion. The rotation shaft 119 penetrates in the axial direction through the second shaft hole. The outer peripheral surface of the bearing receiving portion may be formed to be inclined with respect to the axial direction.

The second journal bearing 1242 may be mounted on the inner surface of the bearing receiving portion. The second journal bearing 1242 is arranged to be spaced apart from the rotation shaft 119 with a gap in the radial direction.

The radial extension portion may extend to protrude radially outward from the outer periphery of the bearing receiving portion. The radial extension may extend along the circumference in a disk shape.

The radial extension may be coupled to the inside of the other end of the housing 100.

The bearing accommodating portion may protrude axially from the radial extension portion toward the second space 118 of the housing 100.

According to this configuration, the first journal bearing 1241 and the second journal bearing 1242 can support the radial load of the rotation shaft 119.

The first thrust bearing 1271 may be mounted on the axial rear side of the first bearing housing 1281. The axial rear surface of the first bearing housing 100 refers to a surface facing in the opposite direction to the first impeller 1231.

A thrust runner 129 is provided on the rotation axis 119. The thrust runner 129 may be used to transmit the axial load of the rotation shaft 119 to the thrust bearing 127.

The thrust runner 129 is formed to protrude radially from the first shaft portion 1191 of the rotation shaft 119 into the first space 117. The thrust runner 129 may rotate together with the rotation axis 119.

The journal bearing 124 and the thrust bearing 127 according to this embodiment may each be implemented as a gas foil bearing.

The gas foil bearing is made to support the rotating shaft 119 by working fluid.

The working fluid may be refrigerant or air. In this embodiment, the working fluid may be a refrigerant.

The gas foil bearing may be arranged to be spaced apart from the rotating shaft 119 at a predetermined distance (air gap).

The gas foil bearing can rotatably support the rotating shaft 119 using a working fluid filled in the gap between the rotating shaft 119 and the bearing.

Since the bearing of the present invention is spaced apart from the rotating shaft 119, it can rotatably support the rotating shaft 119 in a non-contact manner.

According to this, as the rotating shaft 119 rotates at high speed, an air gap is stably formed between the rotating shaft 119 and the bearing, the center of the rotating shaft 119 is placed at the center of the bearing, and the rotating speed increases further. When this happens, the pressure in the air gap increases due to centrifugal force, improving the axial support capacity, making it possible to realize a high-efficiency compressor without friction.

Additionally, the life of the bearing can be extended due to less noise and reduced wear. In addition, the bearing of the present invention does not require lubricating oil, so lubricating oil replacement and maintenance costs are eliminated.

The thrust bearing 127 may be implemented as a gas foil bearing. The thrust bearing 127 may be arranged to overlap the thrust runner 129 in the axial direction.

The thrust bearing 127 may be composed of a first thrust bearing 1271 and a second thrust bearing 1272 depending on the installation location.

The first thrust bearing 1271 may be mounted on the axial rear side of the first bearing housing 1281. The axial front of the first bearing housing 1281 is disposed toward the first impeller 1231, and the axial rear of the first bearing housing 1281 is disposed toward the thrust runner 129.

The second thrust bearing 1272 may be mounted on the front of the partition wall 116. The front of the partition 116 faces the thrust runner 129, and the rear of the partition 116 faces the transmission unit 120.

The first thrust bearing 1271 and the second thrust bearing 1272 are arranged to be spaced apart from the thrust runner 129 at a preset distance in the axial direction.

The description of the thrust bearing 127 can be equally applied to the first thrust bearing 1271 and the second thrust bearing 1272.

The thrust bearing 127 includes a bump foil 1273, a cover foil 1274, and a bearing plate.

Bump foil 1273 is an elastic structure. The bump foil 1273 may be formed by forming a metal thin film in an embossed form.

One side of the bump foil 1273 may be fixed to the bearing plate, and the other side of the bump foil 1273 may be a free end.

The bump foil 1273 may include a plurality of curved portions 1273a and a plurality of connection portions 1273b.

The curved portion 1273a may be formed in an arc shape or a semicircle shape. The connection portion 1273b is formed in a planar shape.

The connecting portion 1273b is formed to connect one end and the other end of two adjacent curved portions 1273a.

A plurality of curved portions 1273a and a plurality of connecting portions 1273b are alternately arranged along one direction. The plurality of curved portions 1273a and the connecting portion 1273b may be formed as one body. In this embodiment, a plurality of curved portions 1273a and a plurality of connecting portions 1273b are alternately arranged along the circumferential direction of the thrust bearing 127.

The plurality of curved portions 1273a may be formed to have the same radius.

The plurality of curved portions 1273a may be formed to be convex in the same direction. The plurality of curved portions 1273a may be formed to be convex from the bearing plate toward the cover foil 1274.

The direction in which the plurality of curved portions 1273a will be convex may be determined depending on the axial load support direction of the bearing.

For example, in the case of the thrust bearing 127, the curved portion 1273a may be formed convex in the axial direction, and in the case of the journal bearing, the curved portion 1273a may be formed convex in the radial direction.

The curved portion 1273a of the thrust bearing 127 is formed to be convex in the axial direction.

The cover foil 1274 is disposed to cover the bump foil 1273. The cover foil 1274 may be called a top foil in that it is disposed to contact the highest vertex of the bump foil 1273.

The cover foil 1274 is disposed to face the thrust runner 129 and to be spaced apart from the thrust runner 129 in the axial direction.

The cover foil 1274 may be composed of a cover extension part, a cover inclined part, and a cover fixing part.

The cover extension portion is disposed to contact the highest point of the curved portion 1273a of the bump foil 1273.

The cover fixing part has a flat shape to fix the cover foil 1274 to the base plate.

The cover inclined portion is formed to be inclined at a preset angle with respect to the bearing plate to connect the cover extension portion and the cover fixing portion.

The bearing plate is configured to secure the thrust bearing 127 to the first bearing housing 1281 or the partition wall 116.

The cover fixing portion of the cover foil 1274 is fixed to the bearing plate, and the cover extension portion of the cover foil 1274 is a free end.

The bearing plate may be formed as a circular plate. A through hole is formed in the bearing plate so that the rotating shaft 119 can pass through. The through hole of the bearing plate is formed larger than the diameter of the rotating shaft 119.

According to this configuration, even if the axial load transmitted to the rotating shaft 119 by the refrigerant suction pressure of the impeller 123 acts on the thrust runner 129, the first thrust bearing 1271 and the second thrust bearing 1272 The axial load of the rotation shaft 119 can be rotatably supported using the elastic force of the bump foil 1273.

The turbo compressor can compress the refrigerant in multiple stages depending on the number of impellers 123. This embodiment shows a two-stage compressor.

The impeller 123 can be divided into a first impeller 1231 to an N-th impeller according to the compression order of the refrigerant. In this embodiment, the impeller 123 is shown to be composed of a first impeller 1231 and a second impeller 1232. The first impeller 1231 may be named the first-stage impeller 123, and the second impeller 1232 may be named the second-stage impeller 123.

In this specification, unless the first impeller 1231 and the second impeller 1232 are separately distinguished, the description of the configuration of the impeller 123 can also be applied to the first impeller 1231 and the second impeller 1232.

Fluids such as refrigerant and/or air may be compressed in the first stage in the first impeller 1231 and then compressed (recompressed) in the second stage in the second impeller 1232.

The impeller 123 is mounted on the rotation shaft 119 to be rotatable together with the rotation shaft 119. The impeller 123 may rotate by receiving power from the transmission unit 120 through the rotation shaft 119.

The impeller 123 rotates with the rotating shaft 119 and sucks fluid such as refrigerant in order to compress the fluid.

A first impeller 1231 support portion and a second impeller 1232 support portion may be provided at both ends of the rotation shaft 119.

The support portion of the first impeller 1231 may have a diameter smaller than that of the rotation shaft 119 and may be formed to protrude in the axial direction from one end of the rotation shaft 119. The support portion of the first impeller 1231 may be press-fitted to the inside of the hub 123a of the first impeller 1231.

The support portion of the second impeller 1232 may have a diameter smaller than that of the rotation shaft 119 and may be formed to protrude in the axial direction from the other end of the rotation shaft 119. The support portion of the second impeller 1232 may be press-fitted to the inside of the hub 123a of the second impeller 1232.

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

The hub 123a has a through hole therein to allow the rotation shaft 119 to pass therethrough. The hub 123a may be formed in a cone shape. The outer peripheral surface of the hub 123a may be formed to be inclined with respect to the axial direction. Based on the suction direction of the working fluid, the diameter of the hub 123a may be formed to increase from the axial front end of the hub 123a to the axial rear end of the hub 123a.

A plurality of blades 123b may be formed to protrude along a spiral from the outer peripheral surface of the hub 123a. The plurality of blades 123b are arranged to be spaced apart in the circumferential direction of the hub 123a.

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

The first impeller casing 111 is fastened to one side of the housing 100. The axial rear surface of the first impeller casing 111 may be covered by the first bearing housing 1281 accommodated on one side of the housing 100.

The second impeller casing 112 is fastened to the other side of the housing 100. The axial rear surface of the second impeller casing 112 may be covered by the second bearing housing 1282 accommodated on the other side of the housing 100. The axial rear side of the first impeller casing 111 and the second impeller casing 112 refers to the downstream side of the impeller 123 casing based on the flow direction of the refrigerant.

The first impeller casing 111 includes intake ports 113a and 113b, diffusers 114a and 114b, and discharge ports 115a and 115b.

The intake ports 113a and 113b are formed to penetrate axially through the center of the first impeller casing 111. One side of the inlet ports 113a and 113b may communicate with the outside of the first impeller casing 111, and the other side of the inlet ports 113a and 113b may communicate with the inside of the first impeller casing 111.

The first impeller 1231 is accommodated inside the intake ports 113a and 113b. The first impeller 1231 is mounted on the first impeller 1231 support portion and can rotate together with the rotation shaft 119.

The intake ports 113a and 113b may be formed to have a diameter that decreases from one axial side to the other axial side. According to this, the flow rate of the refrigerant sucked through the intake ports 113a and 113b may increase.

The diffusers 114a and 114b are formed to be recessed in the axial direction at the axial rear surface of the first impeller casing 111. The diffusers 114a and 114b are formed inside the first impeller casing 111. Diffusers 114a and 114b are disposed between the intake ports 113a and 113b and the discharge ports 115a and 115b.

The diffusers 114a and 114b may be formed to extend in a spiral direction from the intake ports 113a and 113b. The diffusers (114a, 114b) are connected in communication with the intake ports (113a, 113b) and the discharge ports (115a, 115b). The diffusers 114a and 114b are formed so that the size of the flow path increases from the intake ports 113a and 113b to the discharge ports 115a and 115b.

According to this configuration, as the size of the flow path of the diffusers 114a and 114b increases, the pressure of the working fluid sucked by the rotation of the impeller 123 increases as it passes through the diffusers 114a and 114b.

That is, the diffusers 114a and 114b can increase the pressure of the refrigerant by converting the kinetic energy of the refrigerant sucked through the intake ports 113a and 113b into pressure energy.

The discharge ports 115a and 115b are provided on the outer periphery of the first impeller casing 111. The discharge ports 115a and 115b may extend radially from the diffusers 114a and 114b. The discharge pipe may be formed to protrude outward from the outer periphery of the first impeller casing 111.

One side of the discharge pipe may be connected to the discharge ports 115a and 115b, and the other side of the discharge pipe may be connected to the outside of the first impeller casing 111.

The second impeller casing 112 includes intake ports 113a and 113b, diffusers 114a and 114b, and discharge ports 115a and 115b. The inlet ports 113a, 113b, diffusers 114a, 114b, and discharge ports 115a, 115b of the second impeller casing 112 are the inlet ports 113a, 113b, diffusers 114a, 114b of the first impeller casing 111. and the discharge ports 115a and 115b, so duplicate descriptions will be omitted.

However, for two-stage compression, the discharge pipe of the first impeller casing 111 may be connected to the suction ports 113a and 113b of the second impeller casing 112 through a connection pipe (not shown).

Each of the first impeller casing 111 and the second impeller casing 112 may be configured to be separable into two parts.

One part is the suction part (111a, 112a). The suction parts 111a and 112a may be formed to have a T-shaped cross-sectional shape. The suction portions 111a and 112a may be composed of a radial portion extending in the radial direction and an axial portion extending in the axial direction. The suction ports 113a and 113b are formed inside the axial portion of the suction portions 111a and 112a.

The downstream portion of the suction units 111a and 112a may be formed in an arc-shaped curved surface. The downstream portion of the suction portions 111a and 112a is configured to accommodate the impeller 123.

The other part is the diffuser portion (111b, 112b). The diffuser portions 111b and 112b are formed to surround the outer peripheral surface of the radial portion, the rear surface, and the axial portion of the suction portions 111a and 112a. The suction units 111a and 112a and the diffuser units 111b and 112b are coupled to each other.

The rear surface of the radial portion of the suction portions 111a and 112a refers to the downstream surface based on the suction direction of the refrigerant.

To prevent leakage of refrigerant, a radial sealing member and an axial sealing member are provided.

A radial sealing member may be provided between the bearing housing 128 and the impeller 123. In this embodiment, the radial sealing member is shown disposed between the first bearing housing 1281 and the impeller 123.

The radial sealing member may be composed of a first radial sealing part 130 and a second radial sealing part 134.

For example, a first radial sealing portion 130 may be provided on one axial side of the first bearing housing 1281.

The first radial sealing portion 130 may be integrally formed on one axial side of the first bearing housing 1281 or may be coupled to one axial side of the first bearing housing 1281.

In this embodiment, the first radial sealing portion 130 is shown coupled to one axial side of the first bearing housing 1281. To this end, the sealing portion receiving groove 131 may be formed to be recessed in the axial direction to accommodate the first radial sealing portion 130 on one axial side of the first bearing housing 1281.

The first radial sealing portion 130 includes a plurality of sealing grooves 132 and a plurality of first land portions 133.

The plurality of sealing grooves 132 may be formed to be recessed in the axial direction on one axial side (front) of the first radial sealing portion 130 in the direction opposite to the impeller 123. The plurality of sealing grooves 132 may extend along the circumferential direction of the first radial sealing portion 130.

The front of the first radial sealing portion 130 refers to the side facing the impeller 123.

The plurality of sealing grooves 132 may be arranged to be spaced apart in the radial direction of the first radial sealing portion 130.

The plurality of sealing grooves 132 may be arranged to overlap the impeller 123 in the axial direction.

The plurality of first land portions 133 may be disposed between the plurality of sealing grooves 132.

A plurality of sealing grooves 132 and a plurality of first land parts 133 may be alternately arranged in the radial direction of the first radial sealing part 130.

Each of the plurality of sealing grooves 132 and the plurality of first land portions 133 may be formed in an annular shape. However, the radial width of the sealing groove 132 and the radial thickness of the first land portion 133 may be formed differently.

A second radial sealing portion 134 may be provided on the other axial side (rear) of the first impeller 1231. The rear of the first impeller 1231 faces the first radial sealing portion 130.

The second radial sealing portion 134 is disposed on the downstream side of the first impeller 1231 based on the flow direction of the refrigerant. The second radial sealing portion 134 may rotate together with the first impeller 1231.

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

A plurality of sealing protrusions 135 are formed to protrude in the axial direction toward the first radial sealing portion 130 from the other axial side of the hub 123a of the first impeller 1231. The plurality of sealing protrusions 135 may each be accommodated in a plurality of sealing grooves 132.

The sealing protrusion 135 is accommodated in the sealing groove 132 and is spaced apart from the inner surface of the sealing groove 132 at a predetermined distance in the axial and radial directions.

The sealing protrusion 135 extends along the circumferential direction of the hub 123a and may be formed in an annular shape.

The plurality of sealing protrusions 135 and the plurality of first land parts 133 are arranged to overlap in the radial direction.

According to this configuration, the plurality of sealing protrusions 135 and the plurality of first land parts 133 are arranged to overlap in the radial direction, thereby preventing leakage of the refrigerant moving from the impeller 123 to the diffusers 114a and 114b. can do.

For example, when the impeller 123 rotates, the plurality of blades 123b rotate around the hub 123a, so that the impeller 123 directs the refrigerant sucked through the space between the plurality of blades 123b to the diffuser ( It can be moved in the radial direction toward 114a, 114b).

Here, the plurality of sealing protrusions 135 and the first land portion 133 act as flow resistance for the refrigerant flowing from the diffusers 114a and 114b toward the downstream side of the impeller 123, thereby forming the first radial sealing portion ( It is possible to prevent the refrigerant from flowing back radially inward through the gap between the sealing groove 132 of 130) and the rear of the impeller 123.

Additionally, the radial sealing member described above can be equally applied between the second bearing housing 1282 and the second impeller 1232.

The axial sealing member may be provided between the second bearing housing 1282 and the second impeller casing 112. The axial sealing member may be composed of a first axial sealing part 136 and a second axial sealing part.

The first axial sealing portion 136 may be provided inside the diffuser portions 111b and 112b of the second impeller casing 112. The first axial sealing portion 136 may be coupled between the second bearing housing 1282 and the diffuser portions 111b and 112b of the second impeller casing 112.

The first axial sealing portion 136 includes a plurality of sealing grooves. A plurality of sealing grooves may be formed to be recessed in the radial direction on the inner surface of the first axial sealing portion 136.

The sealing groove may be formed in an annular shape. The sealing groove may extend in the circumferential direction along the inner circumference of the first axial sealing portion 136.

A plurality of sealing grooves may be arranged to be spaced apart in the axial direction on the inside of the first axial sealing portion 136. The second land portion may be disposed between the plurality of sealing grooves. A plurality of sealing grooves and a plurality of second land parts may be arranged to be alternately spaced apart along the axial direction on the inner surface of the first axial sealing portion 136.

The second axial sealing part may be provided on the other side of the rotation shaft 119. The second axial sealing part may rotate together with the first impeller (1231). The second axial sealing portion may be disposed to overlap the sealing groove in the radial direction so as to be accommodated in the sealing groove.

The second axial sealing portion includes a plurality of sealing protrusions.

A plurality of sealing protrusions may be formed to protrude radially outward from the outer peripheral surface of the rotating shaft 119 toward the inner surface of the sealing groove. The plurality of sealing protrusions may be formed in an annular shape.

The plurality of sealing protrusions are arranged to be spaced apart from each other in the axial direction on the rotation axis 119.

A plurality of sealing protrusions and a plurality of second land parts may be alternately arranged along the axial direction of the rotation axis 119. The plurality of sealing protrusions and the plurality of second land parts are arranged to be spaced apart from each other at a preset interval in the axial direction.

The plurality of second land portions are arranged to be spaced apart from the rotation axis 119 at a preset distance in the radial direction.

The plurality of sealing protrusions are arranged to be spaced apart from the inner surface of the first axial sealing portion 136 at a preset distance in the radial direction.

The plurality of sealing protrusions and the second land portion are arranged to overlap in the axial direction.

According to this configuration, the plurality of sealing protrusions and the second land portion are arranged to overlap in the axial direction, thereby preventing fluid such as refrigerant sucked by the second impeller 1232 from leaking into the second space 118. .

For example, when the second impeller 1232 rotates, the plurality of blades 123b rotate around the hub 123a, so that the second impeller 1232 flows refrigerant through the space between the plurality of blades 123b. Can be suctioned axially.

Here, the plurality of sealing protrusions and the second land 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 forming the inner portion of the first axial sealing portion 136. It is possible to prevent refrigerant from leaking into the second space 118 through the gap between the side surface and the rotating shaft 119.

The axial sealing member described above can be equally applied between the first bearing housing 1281 and one side of the rotation shaft 119.

(2) Asymmetric thrust bearing(127)

FIG. 4 is a conceptual diagram showing the left and right ends of the rotation axis 119 rotating around the thrust runner 129 in FIG. 3 .

FIG. 5 is a conceptual diagram showing the inside of the second thrust bearing 1272 in FIG. 1 reduced.

FIG. 6 is a conceptual diagram showing a cooling passage added to the inner end of the partition wall 116 where the second thrust bearing 1272 is mounted in FIG. 5.

FIG. 7 is a conceptual diagram showing the cooling passage expanded by removing the inside of the partition wall 116 in FIG. 5 where the second thrust bearing 1272 is not installed.

The turbo compressor converts the velocity energy of the working fluid according to the rotation of the impeller 123 into pressure energy to increase the pressure of the working fluid.

The pressure of the working fluid (compressed in first stage) sucked into the second impeller 1232 is greater than the pressure of the working fluid sucked into the first impeller 1231. In addition, the pressure of the working fluid compressed in the second stage in the second impeller 1232 is greater than the pressure of the working fluid compressed in the first stage in the first impeller 1231.

Accordingly, a pressure difference in the working fluid occurs between the first impeller 1231 and the second impeller 1232, which are rotatably coupled to both ends of the rotating shaft 119, respectively, and this causes the axial direction in the second impeller 1232. An axial load is generated on the rotation shaft 119 toward the first impeller 1231. At this time, the axial load may be named thrust.

The thrust of the impeller 123 can be calculated as the product of the pressure and area in the impeller 123.

The size and direction of thrust are determined by the operating environment of the compressor, and have one direction in most operating areas.

The thrust bearing 127 can support the axial load by the fluid rotated by the thrust runner 129 of the rotation shaft 119 and the shape of the bearing.

While the pressure of the working fluid is increased by the impeller 123, a unilateral axial load acts on the thrust runner 129. Here, the unilateral axial load refers to the axial force in the first direction, that is, from the second impeller 1232 to the first impeller 1231.

Accordingly, the thrust runner 129 moves toward the first thrust bearing 1271 and applies an axial load, so that the first thrust bearing 1271 supports the unilateral axial load.

However, when compressed by the first and second stage impellers 1231 and 1232, the thrust runner 129 does not move in the second direction opposite to the first direction, so the thrust runner moves in the second thrust bearing 1272. ) Do not apply axial load. In this case, the second thrust bearing 1272 does not support the axial load.

When operating a two-stage compression turbo compressor, the second thrust bearing 1272, which does not support the axial load, may lose its function or be reduced.

Therefore, the second thrust bearing 1272 can use an inexpensive bearing rather than an expensive oilless bearing. For example, the second thrust bearing 1272 may use a small and inexpensive bearing such as a self-lubricating coated surface or a tilting pad thrust bearing. A tilting pad thrust bearing is a device configured to distribute the load to each of a plurality of pads so that each pad supports the load evenly.

The maximum load-bearing capacity of the thrust bearing 127, which can support an axial load, is related to the area of the bearing.

Therefore, when the pressure of the working fluid increases due to rotation of the impeller 123, the size of the second thrust bearing 1272, which does not support the axial load, may be reduced. The area where the second thrust bearing 1272 is installed may also be reduced.

In addition, due to the reduction of the second thrust bearing 1272, free space is created on the installation surface (partition wall 116) or the surrounding portion (thrust runner 129) of the reduced second thrust bearing 1272. This free space can be used as a cooling passage.

However, gas foil bearings, a type of oilless bearing, have a small gap (10 μm), making it narrow to form a cooling passage.

Meanwhile, looking at the behavior of the rotation axis 119 with reference to FIG. 4, the behavior of the rotation axis 119 is as follows.

The left and right ends of the rotation axis 119 may rotate around the vertical center line of the thrust runner 129.

Here, the vertical center line of the thrust runner 129 means a straight line passing perpendicularly through the center of the thrust runner 129 in the radial direction.

The thrust runner 129 can rotate left and right about the vertical center line of the thrust runner 129.

The circumferential rotation distance of the thrust runner 129 increases as it moves from the center of the thrust runner 129 to the radial outer end of the thrust runner 129.

For this reason, when the thrust runner 129 rotates left and right, the outer end of the thrust runner 129 can contact the outer end of the thrust bearing 127 rather than the inner end of the thrust runner 129. Here, the outer end of the thrust runner 129 refers to the outer end along the radial direction based on the center of the thrust runner 129, and the inner end of the thrust runner 129 refers to the outer end along the center of the thrust runner 129. Refers to the inner end along the radial direction.

According to the embodiment of FIG. 5, a portion of the inner side of the second thrust bearing 1272 located close to the inner end of the partition wall 116 may be deleted.

The second thrust bearing 1272, whose inner portion has been deleted (reduced), may extend in the circumferential direction of the partition wall 116. A plurality of second thrust bearings 1272 may be provided and arranged to be spaced apart along the circumferential direction.

According to the embodiment of FIG. 6, the cooling passage 1161 may be formed to penetrate the inner end of the partition wall 116 in the axial direction. The cooling passage 1161 connects the first space 117 and the second space 118 in communication.

There may be a plurality of cooling passages 1161. The plurality of cooling passages 1161 may be arranged to be spaced apart in the radial direction. The plurality of cooling passages 1161 may be arranged to be spaced apart in the circumferential direction.

According to this configuration, fluid such as air inside the housing 100 moves between the first space 117 and the second space 118 through the cooling passage 1161 and cools the thrust bearing 127, etc. You can.

According to the embodiment of FIG. 7, the inner end of the partition wall 116 may be deleted. The partially deleted inner space of the partition wall 116 can be used as a cooling passage 1162.

According to this configuration, the radial width of the space between the rotating shaft 119 and the partition wall 116 is widened, so that fluid such as air inside the housing 100 flows through the cooling passage 1162 of the partition wall 116 into the first By moving between the space 117 and the second space 118, the thrust bearing 127, etc. can be cooled.

(3) Asymmetric Thrust Runner(129)

FIG. 8 is a conceptual diagram showing the flow path forming groove 1291 formed on the non-operating bearing surface of the thrust runner 129 in FIG. 3.

The thrust runner 129 is formed in a disk shape. The thrust runner 129 includes a first surface 129a, a second surface 129b, and an outer peripheral surface 129c.

The first surface 129a of the thrust runner 129 is disposed to face the first thrust bearing 1271 in the axial direction. The first surface 129a is formed as a flat surface. The first surface 129a extends to protrude from the rotation axis 119 in the radial direction.

The second surface 129b of the thrust runner 129 is disposed to face the second thrust bearing 1272 in the axial direction. At least part of the second surface 129b is formed as a curved surface.

The first surface 129a and the second surface 129b of the thrust runner 129 are faces facing in opposite directions in the axial direction.

The outer peripheral surface (129c) of the thrust runner 129 extends in the axial direction between the first surface (129a) and the second surface (129b) to connect the first surface (129a) and the second surface (129b). The outer peripheral surface 129c is formed as a circular curved surface. The outer peripheral surface (129c) is located at the outermost part of the thrust runner (129).

As described above, when the two-stage compression turbo compressor is operated, a unilateral axial load is applied to the rotation shaft 119 due to the pressure difference of the working fluid according to the rotation of the impeller 123.

The first thrust bearing 1271 supports an axial load against the first surface 129a of the relatively rotating thrust runner 129, and high temperature heat is generated on the first surface 129a.

However, since the unilateral axial load does not act on the second surface 129b of the relatively rotating thrust runner 129, relatively low temperature heat is generated on the second surface 129b.

A flow path forming groove 1291 may be formed on the second surface 129b. The flow path forming groove 1291 is formed as a curved surface with a preset curvature. The flow path forming groove 1291 is formed to be recessed in the thickness direction or axial direction of the thrust runner 129 on the second surface 129b. The depression depth of the flow path forming groove 1291 may vary along the radial direction of the second surface 129b.

For example, the depression depth of the flow path forming groove 1291 becomes deeper in the axial direction from the radially inner end to the outer end of the thrust runner 129.

The flow path forming groove 1291 may form a cooling flow path to resolve thermal imbalance between the first surface 129a and the second surface 129b of the thrust runner 129. The flow path forming groove 1291 can rotate the cooling fluid inside the housing 100 according to the rotation of the thrust runner 129. The flow path forming groove 1291 is arranged to not overlap the second thrust bearing 1272 in the axial direction.

The flow path forming groove 1291 may be formed radially inside the second surface 129b of the thrust runner 129.

The second surface 129b on which the flow path forming groove 1291 is not formed may be formed as a flat surface. The flat portion of the second surface 129b is arranged to overlap the second thrust bearing 1272 in the axial direction.

The thickness of the thrust runner 129 is constant between the flat portions of the first surface 129a and the second surface 129b, which are the radially outer portions of the thrust runner 129. On the other hand, the thickness of the thrust runner 129 is not constant between the flow path forming grooves 1291 of the first surface 129a and the second surface 129b.

The thickness of the thrust runner 129 increases from the radial outer side to the radial inner side of the flow path forming groove 1291 with respect to the first surface 129a.

The first corner portion 1292 connecting the first surface 129a of the thrust runner 129 and the rotation axis 119 is formed in a curved shape with a preset first curvature.

The second corner portion 1293 connecting the second surface 129b of the thrust runner 129 and the rotation axis 119 is formed in a curved shape with a preset second curvature.

The second curvature of the second corner portion 1293 may be formed to be the same as the curvature of the flow path forming groove 1291. The first curvature is greater than the second curvature. In other words, the second radius of curvature (R2) of the second corner portion (1293) is larger than the first radius of curvature (R1) of the first corner portion (1292).

According to this configuration, the flow path forming groove 1291 forms a cooling flow path through which cooling fluid can flow, thereby cooling the heat of the first thrust bearing 1271 mounted on the first surface 129a of the thrust runner 129. You can do it. Damage to the bearing due to deterioration of the first thrust bearing 1271 can be prevented. The durability of the first thrust bearing 1271 implemented as an expensive gas foil bearing can be improved. By extending the replacement cycle of bearing parts, parts replacement costs can be reduced.

In addition, the flow path forming groove 1291 is formed between the first thrust bearing 1271 and the thrust runner 129 by varying the thickness of the thrust runner 129 along the second surface 129b of the thrust runner 129. The heat generated can be cooled efficiently.

More specifically, the thickness of the thrust runner 129 gradually becomes thinner from the radially inner end of the flow path forming groove 1291 to the radially outer end of the flow path forming groove 1291.

Because of this, the cooling fluid flowing in the flow path forming groove 1291 can secure the minimum distance to more quickly cool the heat of the first thrust bearing 1271 through conduction of the thrust runner 129.

The flow path forming groove 1291 is arranged to overlap in the axial direction with the middle portion connecting the outer end and the inner end of the first thrust bearing 1271, so that the thickness of the thrust runner 129 is reduced, thereby reducing the thickness of the thrust bearing 127. The heat of the first thrust bearing 1271 can be efficiently cooled without reducing the axial load bearing capacity.

If the flow path forming groove 1291 is formed at the outer end of the thrust runner 129, and the rigidity of the outer end of the thrust runner 129 decreases, when both left and right ends of the rotation axis 119 rotate in the vertical direction, the thrust runner ( This is because the outer end of 129) may contact the thrust bearing 127 first, causing problems in the axial load bearing capacity of the thrust bearing 127.

In addition, while the depression depth of the flow path forming groove 1291 decreases from the radial outer side to the inner side, the thickness of the thrust runner 129 is closer to the rotation axis 119 at the radially outer end of the flow path forming groove 1291. As the thickness increases, the axial support rigidity of the thrust runner 129 can be increased.

In addition, the second corner portion 1293 of the thrust runner 129 extending from the flow path forming groove 1291 to the rotation axis 119 has a larger radius of curvature than the first corner portion 1292 of the thrust runner 129, The thickness reduction of the thrust runner 129 due to the formed groove 1291 can be reinforced.

The radially inner end of the flow path forming groove 1291 is located radially outside the first corner portion 1292 of the thrust runner 129.

The axial thickness of the second corner portion 1293 of the thrust runner 129 extending from the radially inner end of the flow path forming groove 1291 to the rotation axis 119 is determined from the first surface 129a of the thrust runner 129. It is thicker than the axial thickness of the first corner portion 1292 of the thrust runner 129 extending to the rotation axis 119.

Through this, the first corner portion 1292 of the thrust runner 129 has a larger radius of curvature than the second corner portion 1293, and the reduction in thickness of the thrust runner 129 due to the flow path forming groove 1291 can be reinforced. .

For example, the ratio R1/R2 of the first radius of curvature (R1) of the first corner portion (1292) and the second radius of curvature (R2) of the second corner portion (1293) may be formed in the range of 1/4 to 1. You can.

This is because, if the R1/R2 values are outside the numerical range, there is a problem in that the effect of reinforcing the thickness of the second corner portion 1293 is reduced.

The ratio T/d of the total thickness (T) of the thrust runner 129 and the maximum depth (d) of the flow path forming groove 1291 may be formed in the range of 2 to 3.

This is because, if the T/d value is less than 2, the depth of the flow path forming groove 1291 becomes too large, thereby weakening the strength of the thrust runner 129, and if it is greater than 3, the size of the cooling flow path becomes small, leading to a problem of reduced cooling performance. there is.

The ratio W1/W2 of the radial width (W1) of the thrust runner 129 and the radial width (W2) of the flow path forming groove 1291 based on the outer peripheral surface of the rotation shaft 119 can be formed in the range of 2 to 3. there is.

This is because, if the W1/W2 value is less than 2, the radial width of the flow path forming groove 1291 becomes too large and the rigidity decreases due to a decrease in the thickness of the thrust runner 129, and if the value is greater than 3, the radius of the flow path forming groove 1291 decreases. There is a problem in that cooling performance deteriorates due to a decrease in the size of the cooling passage as the direction width becomes too small.

Figure 9 is a graph showing the stress of the thrust runner 129 according to the second radius of curvature (R2) of the second corner portion 1293 of the thrust runner 129.

Referring to FIG. 9, as the second radius of curvature of the second corner portion 1293 of the thrust runner 129 increases, the stress of the thrust runner 129 decreases.

However, the thrust runner 129 stress according to the present invention is greater than the thrust runner 129 stress before change, and the minimum value of the thrust runner 129 stress according to the present invention converges to the thrust runner 129 stress before change.

Here, in the thrust runner 129 before change, both the first surface (129a) and the second surface (129b) of the thrust runner 129 are formed as flat surfaces, and the first corner portion 1292 and the second corner portion 1293 ) have the same radius of curvature, and the radii of curvature of the first and second corner portions 1293 before change are smaller than the second radius of curvature of the second corner portion 1293 according to the present invention.

Figure 10 is a graph showing the thrust runner 129 stress according to the thickness of the thrust runner 129.

The stress of the thrust runner 129 whose thickness is reduced is smaller than the stress of the thrust runner 129 before the thickness is reduced.

As the thickness reduction of the thrust runner 129 increases, the stress of the thrust runner 129 gradually decreases compared to the stress of the thrust runner 129 before the thickness reduction.

It is preferable that the thickness reduction of the thrust runner 129 according to the present invention does not exceed a 5% difference between the stress of the thrust runner 129 after the thickness reduction compared to the stress of the thrust runner 129 before the thickness reduction.

Meanwhile, fluid such as air and/or refrigerant may be included inside the housing 100.

The fluid inside the housing 100 may rotate according to the rotation of the thrust runner 129.

The rotating fluid moves from the radially inner end to the radially outer end of the thrust runner 129 along the first surface 129a and the second surface 129b of the thrust runner 129 by centrifugal force.

The first surface 129a of the thrust runner 129 is flat, and the flow path forming groove 1291 formed on the second surface 129b of the thrust runner 129 is curved.

The movement distance of the fluid flowing radially along the first surface (129a) of the thrust runner 129 for the same time is the movement of the fluid flowing along the flow path forming groove 1291 of the second surface (129b) of the thrust runner 129. shorter than the distance

The flow rate of the fluid flowing along the flow path forming groove 1291 of the second surface 129b of the thrust runner 129 is faster than the flow rate of the fluid flowing along the first surface 129a of the thrust runner 129.

According to Bernoulli's principle, when the fluid flows along the first surface (129a) and the second surface (129b) of the thrust runner 129, the pressure in the flow path forming groove (1291) of the second surface (129b) with a high flow velocity is lower than the pressure on the first surface 129a, where the flow rate is relatively slow.

Therefore, an axial force acts on the rotation axis 119 in the opposite direction of the thrust due to the pressure difference due to the movement of fluid on the first surface 129a and the second surface 129b of the thrust runner 129.

The flow path forming groove 1291 formed on the second surface 129b of the thrust runner 129 generates an axial force in the opposite direction of the thrust, thereby canceling out part of the thrust to reduce the axial load.

The flow path forming groove 1291 may be selectively applied to the second surface 129b of the thrust runner 129 as needed. In this embodiment, the flow path forming groove 1291 is shown formed on the second surface 129b of the thrust runner 129.

(4) Thrust runner (129) 1 with cooling fan (140)

Figure 11 is a conceptual diagram showing the cooling fan 140 installed on the thrust runner 129 according to an embodiment of the present invention.

This embodiment is different from the embodiments of FIGS. 1 to 10 in that the cooling fan 140 is formed on the second surface 129b of the thrust runner 129.

The cooling fan 140 is formed integrally with the second surface 129b of the thrust runner 129. The cooling fan 140 may suck the cooling fluid inside the housing 100 in a first direction. The cooling fluid in the second space 118 may be sucked into the first space 117 by the cooling fan 140.

The second surface 129b of the thrust runner 129 includes a flat portion 1294, a cooling fan 140, and a second corner portion 1293.

The flat portion 1294 is formed to surround the cooling fan 140. The flat portion 1294 is disposed on the radial outer side of the second surface 129b. The flat portion 1294 is disposed to face the second thrust bearing 1272. The flat portion 1294 is disposed to overlap the second thrust bearing 1272 in the axial direction.

The cooling fan 140 is arranged to not overlap the second thrust bearing 1272.

The cooling fan 140 includes a protrusion receiving groove 141 and a plurality of rotating protrusions 142.

The protrusion receiving groove 141 is formed to be recessed in the axial direction from the flat portion 1294 toward the first surface 129a of the thrust runner 129. The protrusion receiving groove 141 is formed to extend along the circumferential direction.

The protrusion receiving groove 141 is formed in a curved shape with a preset radius of curvature (R2) and may be formed in a flat shape. In this embodiment, the protrusion receiving groove 141 is shown to be formed in a planar shape. However, the protrusion receiving groove 141 is formed to be more recessed in the axial direction than the flat portion 1294.

A first curved portion is provided at the inner end of the protrusion receiving groove 141. The first curved portion is formed to connect the inner end of the protrusion receiving groove 141 and the second corner portion 1293 of the thrust runner 129. The first curved portion may be formed in a curved shape having the same curvature as the first corner portion 1292.

A second curved portion is provided at the outer end of the protrusion receiving groove 141. The first curved portion is formed to connect the outer end of the protrusion receiving groove 141 and the flat portion 1294. The second curved portion may be formed in a curved shape with a preset curvature.

The plurality of rotating protrusions 142 are accommodated in the protrusion receiving groove 141. A plurality of rotating protrusions 142 are formed to protrude in the axial direction from the protrusion receiving groove 141. The plurality of rotating protrusions 142 are arranged to be spaced apart in the circumferential direction of the protrusion receiving groove 141. The plurality of rotating protrusions 142 may be spaced apart at equal intervals.

The rotating protrusion 142 may be formed in an arc shape.

The rotating protrusion 142 includes a first arcuate surface 1421, a second arcuate surface 1422, a connection surface 1423, an outer end surface 1424, and an inner end surface 1425.

The first arc surface 1421 and the second arc surface 1422 are formed as arc-shaped curved surfaces with different curvatures. The first curvature of the first arcuate surface 1421 is greater than the second curvature of the second arcuate surface 1422. The first arcuate surface 1421 and the second arcuate surface 1422 are formed to extend in an arc shape between the outer and inner ends of the protrusion receiving groove 141.

The first arcuate surface 1421 and the second arcuate surface 1422 are arranged to face opposite directions in the circumferential direction of the protrusion receiving groove 141. The first circular arc surface 1421 may be concave in one direction (clockwise) of the circumferential direction and open in the other direction (counterclockwise) of the circumferential direction.

The second circular arc surface 1422 may be formed to be convex in one direction of the circumferential direction and closed in the other direction of the circumferential direction.

The connection surface 1423 is formed to connect the first arcuate surface 1421 and the second arcuate surface 1422. The connection surface 1423 extends in an arc shape between the outer and inner ends of the protrusion receiving groove 141.

The outer end surface 1424 of the rotating protrusion 142 is formed to connect the outer end of the first circular arc surface 1421 and the outer end of the second circular arc surface 1422.

The inner end surface 1425 of the rotating protrusion 142 is formed to connect the inner end of the first arcuate surface 1421 and the inner end of the second arcuate surface 1422.

The width of the rotating protrusion 142 is smaller than the radial width of the protrusion receiving groove 141. The width of the rotating protrusion 142 is smaller than the circumferential spacing of the plurality of rotating protrusions 142.

Hereinafter, the operating state of the thrust runner 129 equipped with the cooling fan 140 will be described as follows.

As the thrust runner 129 equipped with the cooling fan 140 rotates together with the rotation shaft 119, the rotation protrusion 142 formed on the second surface 129b rotates counterclockwise.

The cooling fluid in the gap between the first thrust bearing 1271 and the first surface 129a may be rotated in the circumferential direction. The cooling fluid in the gap between the first thrust bearing 1271 and the first surface 129a moves radially outward from the inside of the first surface 129a by centrifugal force. Since the first surface (129a) is flat, the cooling fluid moves straight along the first surface (129a).

The cooling fluid in the gap between the second thrust bearing 1272 and the second surface 129b is rotated in the circumferential direction (counterclockwise) by the plurality of rotating protrusions 142.

In addition, the cooling fluid passes through the first curved portion of the second surface 129b by centrifugal force and enters between a plurality of rotating protrusions 142 adjacent to the circumferential direction at the inner end of the protrusion receiving groove 141.

Subsequently, the cooling fluid curves along the first and second arcuate surfaces 1421 and 1422 of the rotating protrusion 142 from the inner end of the protrusion receiving groove 141 toward the outer end of the protrusion receiving groove 141. Go to the path.

Subsequently, the cooling fluid flows from the outer end of the protrusion receiving groove 141, passes through the second curved portion of the second surface 129b, and flows out into the first space 117 through the flat portion 1294 of the second surface 129b. do.

According to this configuration, the cooling fluid flowing along the first surface (129a) of the thrust runner 129 moves in a straight path, and the cooling fluid flowing along the second surface (129b) of the thrust runner 129 moves in a protrusion receiving groove. It can move in a curved path such as the first curved portion of 141, the first arcuate surface 1421, the second arcuate surface 1422, and the second curved portion.

Accordingly, the moving distance of the cooling fluid flowing along the second surface (129b) of the thrust runner 129 during the same time is longer than the moving distance of the cooling fluid flowing along the first surface (129a) of the thrust runner 129. , the flow rate of the cooling fluid on the second surface (129b) is faster than the flow rate of the cooling fluid on the first side (129a).

Therefore, according to Bernoulli's principle, the pressure of the cooling fluid on the first side (129a) with a slow flow rate is greater than the pressure of the cooling fluid on the second side (129b) with a high flow rate, so that the pressure of the cooling fluid on the second side (129b) with a high flow rate As axial force is generated, axial load can be reduced.

Additionally, the thrust runner 129 may function as a cooling fan 140 to provide power to the cooling fluid inside the housing 100. The plurality of rotating protrusions 142 may circulate the fluid inside the housing 100. The plurality of rotating protrusions 142 may move the fluid in the second space 118 to the first space 117.

Cooling fluid in the second space 118 inside the housing 100 may be sucked into the first space 117 by the rotating protrusion 142. The cooling fluid flows in through the gap between the second thrust bearing 1272 and the thrust runner 129, and is supplied to the gap between the first thrust bearing 1271 and the thrust runner 129, so that the first thrust bearing 1271 ) and the heat of the second thrust bearing 1272 can be cooled.

Since other components are the same or similar to the embodiments of FIGS. 1 to 10, duplicate descriptions will be omitted.

(5) Thrust runner (129) 2 with cooling fan (240)

Figure 12 is a conceptual diagram showing the cooling fan 240 installed on the thrust runner 129 according to another embodiment of the present invention.

The shape of the cooling fan 240 in this embodiment is different from the embodiment in FIG. 11.

The cooling fan 240 includes a blade receiving groove 241 and a plurality of blades 242.

The blade receiving groove 241 may be formed on the radial inner side of the second surface 129b of the thrust runner 129. The blade receiving groove 241 is formed to be recessed in the axial direction on the second surface 129b of the thrust runner 129.

The blade receiving groove 241 extends along the circumferential direction. The blade receiving groove 241 may have a constant radial width.

The plurality of blades 242 are formed to protrude in the axial direction from the blade receiving groove 241.

The blade 242 may be composed of a curved portion 2421, a first blade portion 2422, and a second blade portion 2423. The curved portion 2421 may be formed at the inner end of the blade receiving groove 241 in a curved shape having the same curvature as the second corner portion 1293 of the second surface 129b.

The first blade portion 2422 may obliquely extend from the curved portion 2421 toward the outer end of the blade receiving groove 241 at a preset angle with respect to the radial direction.

The second blade portion 2423 may be formed to extend in the circumferential direction from the outer end of the first blade portion 2422.

The plurality of first blade portions 2422 are arranged to be spaced apart from each other at a first interval in the circumferential direction. An inlet may be formed between inner ends of the plurality of first blade portions 2422. The size of the inlet corresponds to the first gap. The width of the first blade portion 2422 is smaller than the first gap.

The plurality of second blade portions 2423 are arranged to be spaced apart at a second interval in the circumferential direction. An outlet may be formed between the plurality of second blade portions 2423. The size of the outlet corresponds to the first gap. The width of the second blade portion 2423 is larger than the second gap and smaller than the first gap.

The first interval is larger than the second interval. The size of the inlet (circumferential width) is larger than the size of the outlet (circumferential width).

According to this configuration, the blades 242 are formed in a “V” shape, thereby securing a wide space for the cooling fluid to remain in the blade receiving groove 241 between the plurality of blades 242.

Since the inlet between the plurality of blades 242 is wider than the outlet, a larger amount of cooling fluid can be sucked in.

In addition, since the outlet between the plurality of blades 242 is narrower than the inlet, it acts like a nozzle, thereby activating the flow of fluid in the first space 117 of the housing 100, thereby improving cooling performance.

The plurality of blades 242 serve as a cooling fan 240 and move in the direction opposite to the thrust due to the pressure difference between the cooling fluids flowing on the first surface 129a and the second surface 129b of the thrust runner 129, respectively. It can generate power.

In addition, the plurality of blades 242 serve as a cooling fan 240 to suck the cooling fluid inside the housing 100, and the cooling fluid is transmitted through heat conduction of the thrust runner 129 to the first thrust bearing 1271. can cool the heat.

Since other components are the same or similar to the embodiments of FIGS. 1 to 11, duplicate descriptions will be omitted.

(6) Thrust runner (129) 3 with cooling fan (340)

Figure 13 is a conceptual diagram showing the cooling fan 340 installed on the thrust runner 129 according to another embodiment of the present invention.

The shape of the cooling fan 340 in this embodiment is different from the embodiments of FIGS. 11 and 12.

The cooling fan 340 may include a blade receiving portion 341 and a plurality of blade protrusions 342.

The blade receiving portion 341 may be formed to be recessed in the axial direction on the second surface 129b of the thrust runner 129.

A plurality of blade protrusions 342 may be formed to protrude from the blade receiving portion 341 in the axial direction.

The blade protrusion 342 may be formed to be longer in length compared to the width. The blade protrusion 342 may extend obliquely between the inner end of the blade accommodating portion 341 and the outer end of the blade accommodating portion 341 or may be formed to be curved with a gentle curvature.

In this embodiment, the blade protrusion 342 may be formed to be curved with a gentle curvature.

The blade protrusion 342 includes a first curved surface 3421, a second curved surface 3422, an inner end surface 3423, an outer end surface 3424, and a connection surface 3425.

The first curved surface 3421 and the second curved surface 3422 are arranged to face opposite directions in the circumferential direction.

The first curved surface 3421 is formed to be curved with a gentle first curvature. The second curved surface 3422 is formed to be curved with a gentle second curvature.

For example, the first curved surface 3421 is arranged to face counterclockwise, and the second curved surface 3422 is arranged to face clockwise.

The inner end surface 3423 is formed to connect the inner end of the first curved surface 3421 and the inner end of the second curved surface 3422. The inner end surface 3423 is disposed to face radially inward at the inner end of the blade receiving portion 341.

The outer end surface 3424 is formed to connect the outer end of the first curved surface 3421 and the outer end of the second curved surface 3422. The outer end surface 3424 is disposed to face radially outward at the outer end of the blade receiving portion 341.

The connection surface 3425 is formed to connect the first curved surface 3421, the second curved surface 3422, the inner end surface 3423, and the outer end surface 3424.

The plurality of blade protrusions 342 are arranged to be spaced apart in the circumferential direction of the blade receiving portion 341. The plurality of blade protrusions 342 may be formed so that the circumferential spacing between the blade protrusions 342 gradually widens from the inside to the outside of the blade receiving portion 341.

An inlet may be formed between inner ends of a plurality of blade protrusions 342 adjacent to each other in the circumferential direction.

An outlet may be formed between outer ends of a plurality of blade protrusions 342 adjacent to each other in the circumferential direction.

The circumferential width (size) of the outlet is larger than the circumferential width (size) of the inlet.

The width of the blade protrusion 342 is smaller than the spacing between the plurality of blade protrusions 342.

Hereinafter, the operating state of the thrust runner 129 3 equipped with the cooling fan 340 and the movement path of the cooling fluid will be described as follows.

As the thrust runner 129 rotates, the cooling fluid flowing along the first surface 129a of the thrust runner 129 moves in a straight line.

The cooling fluid flowing along the second surface 129b of the thrust runner 129 flows into an inlet between a plurality of blade protrusions 342 adjacent in the circumferential direction at the curved portion 2421 of the second surface 129b.

Next, the introduced cooling fluid moves curvedly along the first curved surface 3421 and the second curved surface 3422 of the blade protrusion 342.

Subsequently, it is distributed outward in the radial direction of the thrust runner 129 through the outlet between the plurality of blade protrusions 342.

According to this configuration, the plurality of blade protrusions 342 curve the cooling fluid along the first curved surface 3421 and the second curved surface 3422, thereby forming the first surface 129a and the second surface 129b. The axial load can be reduced by generating a force in the opposite direction of the thrust due to the pressure difference between the cooling fluids.

The plurality of blade protrusions 342 serve as cooling fans 340 to flow the cooling fluid inside the housing 100 and suck the fluid from the second space 118 into the first space 117, thereby allowing the cooling fluid to flow. The first thrust bearing 1271 can be efficiently cooled through heat conduction of the thrust runner 129.

Since other components are the same or similar to the embodiments of FIGS. 1 to 12, duplicate descriptions will be omitted.

(7) Thrust runner (129) 4 with cooling fan (440)

Figure 14 is a conceptual diagram showing the cooling fan 440 installed on the thrust runner 129 according to another embodiment of the present invention.

The shape of the cooling fan 440 in this embodiment is different from the embodiments of FIGS. 11 to 13.

The cooling fan 440 is formed on the second surface 129b of the thrust runner 129.

The cooling fan 440 includes a plurality of rotating ribs 441, a circular rib 442, and a plurality of flow path forming grooves 443.

The plurality of rotating ribs 441 are formed to protrude in the axial direction from the plurality of flow path forming grooves 443. The rotating rib 441 extends in the radial direction. The inner end of the rotating rib 441 is connected to the rotating shaft 119, and the outer end of the rotating rib 441 is connected to the inner peripheral surface of the circular rib 442.

The plurality of rotating ribs 441 are arranged to be spaced apart at equal intervals along the circumferential direction.

The rotating rib 441 has a thin width and a radial length that is longer than the width.

The circular rib 442 is formed to protrude in the axial direction from the flat portion 1294 of the second surface 129b. The circular rib 442 is formed in a circular shape. The circular rib 442 has a thin radial width and a circumferential length that is longer than the radial width.

The circular ribs 442 are formed to surround a plurality of flow path forming grooves 443.

The circular rib 442 and the rotating rib 441 may be formed to have the same protrusion length.

A plurality of flow path forming grooves 443 are formed to be recessed in the axial direction in the flat portion 1294 of the second surface 129b.

The circumferential width of the flow path forming groove 443 increases as it moves from the rotation axis 119 to the circular rib. The circumferential width of the flow path forming groove 443 decreases as it moves from the circular rib to the rotation axis 119.

The flow path forming groove 443 has a deeper axial depth as it moves from the circular rib 442 to the rotation axis 119.

The width of the rotating rib 441 may be smaller than or equal to the minimum spacing of the flow path forming grooves 443. In this embodiment, the width of the rotating rib 441 is smaller than the minimum spacing of the flow path forming groove 443.

Hereinafter, the operating state of the thrust runner 129 equipped with the cooling fan 440 and the movement path of the cooling fluid will be described as follows.

As the thrust runner 129 rotates, the plurality of rotating ribs 441 rotate the cooling fluid contained in the flow path forming groove 443.

Cooling fluid may flow into the inner end of the flow path forming groove 443.

The cooling fluid flowing into the flow path forming groove 443 is rotated by a plurality of rotating ribs 441.

The rotating cooling fluid moves radially outward from the inner end of the flow path forming groove 443 by centrifugal force. The cooling fluid that has moved to the outer end of the flow path forming groove 443 may flow outward from the flow path forming groove 443 in the radial direction.

The leaked cooling fluid may flow into the gap between the second surface 129b of the thrust runner 129 and the second thrust bearing 1272.

According to this configuration, the cooling fan 440 sucks the cooling fluid inside the housing 100 into the flow path forming groove 443. The cooling fluid sucked into the flow path forming groove 443 performs heat exchange through heat conduction between the first surface (129a) and the second surface (129b) of the thrust runner 129, thereby cooling the first thrust bearing 1271. can do.

The depth of the flow path forming groove 443 is formed deeper as it goes from the circular rib 442 toward the rotation axis 119, so that the thickness between the first surface 129a and the second surface 129b of the thrust runner 129 is As the thrust runner 129 becomes thinner toward the inside, heat exchange performance due to heat conduction can be improved.

Additionally, the flow path forming groove 443 forms a curved surface on the second surface 129b of the thrust runner 129. The first surface 129a of the thrust runner 129 forms a plane. The flow rate of the cooling fluid rotating along the flow path forming groove 443 is faster than the flow rate of the cooling fluid flowing along the first surface (129a) of the thrust runner 129, so the cooling fluid pressure on the second surface (129b) is It is lower than the cooling fluid pressure on the first side (129a). Accordingly, the flow path forming groove 443 generates an axial force in the direction opposite to the thrust, that is, from the first impeller 1231 to the second impeller 1232, thereby reducing the axial load.

(8) Thrust runner (129) 5 with cooling fan (540)

Figure 15 is a conceptual diagram showing the cooling fan 540 installed on the thrust runner 129 according to another embodiment of the present invention.

The shape of the cooling fan 540 in this embodiment is different from the embodiments of FIGS. 11 to 14.

The cooling fan 540 includes a plurality of spiral protrusions 541 and a plurality of spiral grooves 542.

A plurality of spiral protrusions 541 are formed to protrude in the axial direction from the second surface 129b. The spiral protrusion 541 extends in a spiral shape. The spiral protrusion 541 is thin and extends longer than the width.

The spiral protrusion 541 includes a first spiral curved surface 5411, a second spiral curved surface 5412, a connecting surface 5413, and an inner curved surface 5414.

The first spiral curved surface 5411 forms one side of the spiral protrusion 541 in the circumferential direction. The second spiral curved surface 5412 forms the other circumferential side surface of the spiral protrusion 541.

The first spiral curved surface 5411 and the second spiral curved surface 5412 are arranged to face opposite directions in the circumferential direction. The first spiral curved surface 5411 has a preset first curvature. The first spiral curved surface 5411 extends in a spiral shape.

The second spiral curved surface 5412 has a preset second curvature. The second spiral curved surface 5412 extends in a spiral shape. The second curvature is greater than the first curvature.

The connection surface 5413 extends in a spiral shape to connect the first spiral curved surface 5411 and the second spiral curved surface 5412.

The inner curved surface 5414 is formed in an arc shape to connect the inner ends of each of the plurality of spiral protrusions 541 adjacent in the circumferential direction. The curvature of the inner curved surface 5414 is smaller than that of the first spiral curved surface 5411.

A spiral groove 542 is formed between a plurality of spiral protrusions 541 adjacent to each other in the circumferential direction.

The spiral groove 542 is formed to be recessed in the axial direction on the second surface 129b of the thrust runner 129. The spiral groove 542 may be formed in a flat shape with a constant axial depth.

A plurality of spiral protrusions 541 and a plurality of spiral grooves 542 are arranged to be alternately spaced apart in the circumferential direction.

An inner curved surface 5414 is formed on the inside of the spiral groove 542 in the spiral direction. It is formed to be open in the spiral direction on the outer side of the spiral groove 542 in the spiral direction.

The width of the spiral groove 542 may be formed to gradually increase from the inside of the spiral groove to the outside of the spiral groove.

The width of the spiral protrusion 541 is smaller than the width of the spiral groove 542.

According to this configuration, the cooling fan 540 sucks the cooling fluid inside the housing 100 into the spiral groove 542. The cooling fluid sucked into the spiral groove 542 performs heat exchange through heat conduction between the first surface (129a) and the second surface (129b) of the thrust runner 129, thereby cooling the first thrust bearing 1271. You can.

Additionally, the spiral groove 542 forms a curved surface on the second surface 129b of the thrust runner 129. The first surface 129a of the thrust runner 129 forms a plane. The flow rate of the cooling fluid rotating along the spiral groove 542 of the second surface (129b) is faster than the flow rate of the cooling fluid flowing along the first surface (129a) of the thrust runner 129, so that The cooling fluid pressure is lower than the cooling fluid pressure at the first surface (129a). Therefore, the spiral groove 542 generates an axial force in the direction opposite to the thrust, that is, from the first impeller 1231 to the second impeller 1232, thereby reducing the axial load.

100: Housing 110: Impeller casing
111: first impeller casing 112: second impeller casing
111a, 112a: suction part 111b, 112b: diffuser part
113a, 113b: Inlet 114a, 114b: Diffuser
115a, 115b: outlet 116: partition wall
1161, 1162: Cooling passage 117: First space
118: second space 119: rotation axis
1191: 1st axis part 1192: 2nd axis part
120: electric unit 121: stator
1211: stator core 1212: stator coil
122: rotor 1221: permanent magnet
1222: Sleeve 123: Impeller
1231: first impeller 1232: second impeller
123a: hub 123b: blade
124: Journal bearing 1241: First journal bearing
1242: second journal bearing 127: thrust bearing
1271: first thrust bearing 1272: second thrust bearing
1273: bump foil 1273a: curved portion
1273b: Connection 1274: Cover foil
128: Bearing housing 1281: First bearing housing
1281a: first radial housing 1281b: second radial housing
1281c: Axial connection 1282: Second bearing housing
129: Thrust runner 129a: First side
129b: 2nd side 129c: outer peripheral surface
1291: Flow path forming groove 1292: First corner part
1293: second corner part 1294: flat part
130: first radial sealing portion 131: sealing portion receiving groove
132: Sealed groove 133: First land portion
134: Second radial sealing part 135: Seal protrusion part
136: first axial sealing part 140: cooling fan
141: projection receiving groove 142: rotating projection
1421: 1st circular surface 1422: 2nd circular surface
1423: Connection surface 1424: Outer cross section
1425: inner cross section 240: cooling fan
241: Blade receiving groove 242: Blade
2421: curved portion 2422: first blade portion
2423: Second blade portion 340: Cooling fan
341: Blade receiving portion 342: Blade protrusion
3421: First curved surface 3422: Second curved surface
3423: inner cross section 3424: outer cross section
3425: Connection surface 440: Cooling fan
441: Rotating rib 442: Circular rib
443: Flow path forming groove 540: Cooling fan
541: Spiral protrusion 5411: First spiral curved surface
5412: Second spiral curved surface 5413: Connection surface
5414: inner curved surface 542: spiral groove

Claims (17)

housing;
a rotating shaft rotatably mounted inside the housing;
an impeller coupled to the rotating shaft and rotating;
A thrust runner formed to protrude in a radial direction from the rotation axis; and
It includes a thrust bearing that supports the axial load generated on the thrust runner when the pressure of the working fluid increases by the impeller,
The thrust runner is,
a first surface disposed toward the axial direction where the axial load acts;
a second surface disposed facing in an opposite direction to the first surface; and
A turbocompressor including a flow path forming groove that is recessed in the axial direction on the second surface to form a flow path through which cooling fluid inside the housing flows. According to paragraph 1,
The thrust bearing is,
a first thrust bearing disposed to face the first surface;
A turbo compressor including a second thrust bearing disposed to face the second surface and non-overlapping in the axial direction with the flow path forming groove. According to paragraph 1,
A turbocompressor wherein the first surface is formed as a flat surface and the second surface is formed as a curved surface. According to paragraph 1,
The flow path forming groove is a turbo compressor formed on a radial inner side of the thrust runner. According to paragraph 1,
The turbocompressor wherein the flow path forming groove is formed as a curved surface with a preset curvature, and the depression depth of the flow path forming groove increases from the radial inner side to the outer side of the thrust runner. According to paragraph 1,
The first corner portion connecting the first surface and the rotation shaft, and the second corner portion connecting the passage forming groove and the rotation shaft are each formed as curved surfaces with different curvatures, and the radius of curvature of the second corner portion is Turbo compressor larger than the radius of curvature of one corner. According to clause 6,
The first corner portion connecting the first surface and the rotation shaft, and the second corner portion connecting the passage forming groove and the rotation shaft each have different axial thicknesses, and the axial thickness of the second corner portion is the second corner portion. Turbo compressor larger than the axial thickness of one corner. According to paragraph 1,
The thrust bearing is,
a first thrust bearing disposed to face the first surface; and
A second thrust bearing faces the radial outer side of the second surface and is disposed to non-overlap in the axial direction with the flow path forming groove formed on the radial inner side of the second surface,
a partition formed to protrude radially inward from the inner peripheral surface of the housing and on which the second thrust bearing is mounted; and
A turbocompressor further comprising a cooling passage provided between a radially inner end of the partition and the rotation shaft and disposed to overlap the passage forming groove in the axial direction. According to paragraph 1,
The thrust bearing is,
a first thrust bearing disposed to face the first surface; and
A second thrust bearing faces the radial outer side of the second surface and is disposed to non-overlap in the axial direction with the flow path forming groove formed on the radial inner side of the second surface,
a partition formed to protrude radially inward from the inner peripheral surface of the housing and on which the second thrust bearing is mounted; and
A turbocompressor further comprising a cooling passage formed to penetrate axially through the radial inner side of the partition wall and disposed to overlap the passage forming groove in the axial direction. housing;
a rotating shaft rotatably mounted inside the housing;
an impeller coupled to the rotating shaft and rotating;
a thrust runner that protrudes radially from the rotation axis and has first and second surfaces facing opposite directions in the axial direction;
a first thrust bearing disposed to face the first surface on which an axial load acts when the pressure of the working fluid is increased by the impeller and supporting the axial load;
a second thrust bearing disposed to face the second surface on which the axial load does not act; and
A turbo compressor including a cooling fan provided on a radial inner side of the second surface and disposed to non-overlap in the axial direction with the second thrust bearing. According to clause 10,
The cooling fan is,
a protrusion receiving groove formed to be recessed in the axial direction on the second surface and extending in the circumferential direction; and
A turbocompressor comprising a plurality of rotating protrusions that are formed to protrude in the axial direction from the protrusion-receiving groove and are spaced apart in the circumferential direction of the protrusion-receiving groove. According to clause 11,
A turbo compressor wherein the rotating protrusion extends in a semicircle between the inner and outer sides of the protrusion receiving groove. According to clause 10,
The cooling fan is,
a blade receiving groove formed to be recessed in the axial direction on the second surface and extending along the circumferential direction;
a first blade portion formed between the inner and outer sides of the blade receiving groove and inclined at a preset angle with respect to the radial direction; and
A turbo compressor including a second blade portion extending in a circumferential direction from an outer end of the first blade portion. According to clause 10,
The cooling fan is,
a blade receiving portion formed to be recessed in the axial direction on the second surface and extending along the circumferential direction; and
A turbocompressor including a plurality of blade protrusions that extend obliquely at a preset angle with respect to the radial direction or extend with a preset curvature between the inner and outer sides of the blade receiving portion. According to clause 10,
The cooling fan is,
a plurality of rotating ribs formed to protrude in the axial direction from the second surface and extending along a radial direction;
a plurality of flow path forming grooves formed to be recessed in the axial direction on the second surface and formed between the plurality of rotating ribs adjacent to each other in the circumferential direction; and
A turbo compressor including a circular rib extending circularly to connect outer ends of the plurality of rotating ribs. According to clause 10,
a plurality of spiral protrusions formed to protrude in the axial direction from the second surface and extending helically; and
A turbocompressor comprising a plurality of spiral grooves formed to be recessed in the axial direction on the second surface and formed between the plurality of spiral protrusions adjacent to each other in the circumferential direction. According to any one of paragraphs 2 and 8 to 16,
An electric unit connected to the rotation shaft to rotate the impeller; and
An impeller casing that accommodates the impeller and has a diffuser that extends spirally from one side of the impeller and compresses the refrigerant sucked by the impeller,
The impeller is,
A first impeller rotatably coupled to one end of the rotating shaft; and
It includes a second impeller rotatably coupled to the other end of the rotating shaft,
The diffuser,
A first diffuser that compresses the working fluid sucked through the first impeller; and
It includes a second diffuser that recompresses the compressed working fluid sucked from the first diffuser through the second impeller,
The first thrust bearing supports the axial load from the second impeller toward the first impeller.

Images