Thrust bearing and turbo compressor comprising same

Abstract

Disclosed are a thrust bearing and a turbo compressor comprising same. The thrust bearing comprises a bearing shell. The bearing shell may support the thrust bearing. The bearing shell comprises a shell body and a shell cover. The shell cover is configured to cover the shell body. The shell body has a cooling flow path therein. The shell cover has an injection hole which is slantly formed and communicates with the cooling flow path. A refrigerant of a condenser may be supplied to the compressor. The refrigerant may be supplied to a gap between the thrust bearing and a thrust runner through the cooling flow path and the injection hole to cool the thrust bearing.

Description

Thrust bearing and turbocompressor equipped therewith

[0001] The present invention relates to a thrust bearing capable of sufficiently securing a flow rate of the operating fluid of the bearing and sufficiently cooling heat caused by friction of the fluid, and to a turbocompressor equipped with the same.

[0002] A turbo compressor compresses the working gas by rotating the impeller at high speed and applying centrifugal force, thereby converting some of the velocity energy into pressure energy.

[0003] Meanwhile, thrust bearings support axial loads by forming a pressure field through relative rotational motion between the thrust runner and the thrust bearing as the rotating shaft of a rotating device such as a turbo compressor rotates.

[0004] In order to form the above pressure field, the flow rate of the working fluid, such as the refrigerant, must be supplied sufficiently and smoothly.

[0005] Additionally, while the thrust bearing is in operation, a gap between the thrust runner of the rotating shaft and the thrust bearing may be formed narrowly, for example, 3 to 6 μm. Heat is generated due to friction of the fluid in the gap, requiring sufficient cooling.

[0006] Thrust bearings can use rolling element bearings such as ball bearings and roller bearings, or fluid bearings such as dynamic bearings and hydrostatic bearings.

[0007] Dynamic bearings support loads by generating a pressure field through wedge and squeeze film effects during relative motion between the rotating shaft and the bearing. The load-bearing capacity, rigidity, and damping of dynamic bearings are determined by their rotational speed and bearing area.

[0008] Bearing cooling methods can be divided into a direct cooling method that cools the bearing by directly supplying coolant to the bearing from the outside, and an indirect cooling method that forms a circulation path around the bearing and indirectly supplies coolant to the bearing through the circulation path.

[0009] Generally, when a rotating machine using a fluid bearing adopts a direct cooling method, a liquid coolant can be supplied to the inside of the bearing.

[0010] However, if liquid coolant is supplied to the air gap (fluid film) formed between the bearing and the rotating body while the bearing is operating, the liquid coolant impacts the fluid film, causing the shaft behavior to become unstable.

[0011] Additionally, there is a problem that wear or failure occurs due to contact friction between the shaft and the bearing as the load-bearing capacity is reduced.

[0012] When the above-mentioned rotating machine adopts an indirect cooling method, there is a problem in that the coolant flow rate is not sufficiently supplied to the bearings. In addition, the heat generated in the bearings cannot be sufficiently cooled.

[0013] The purpose of the present invention is to provide a thrust bearing having a structure capable of solving the above-described problems and a turbocompressor having the same.

[0014] The first purpose is to provide a thrust bearing having a structure capable of sufficiently and smoothly supplying the flow rate of the operating fluid of the bearing without impacting the fluid film between the bearing and the rotating body, and a turbo compressor equipped with the same.

[0015] The second purpose is to provide a thrust bearing having a structure capable of sufficiently cooling heat resulting from fluid friction of the bearing and a turbo compressor equipped with the same.

[0016] The third purpose is to provide a thrust bearing having a structure capable of preventing the inflow of liquid refrigerant into the bearing and a turbo compressor equipped with the same.

[0017] As a result of intensive research, the inventors of the present invention have found that the first to third objectives of the present invention can be achieved by the following embodiments of the present invention.

[0018] In order to achieve the above-described object, a thrust bearing according to one embodiment of the present invention is disposed with a thrust runner and a gap therebetween. The thrust runner is formed to protrude in a radial direction of the rotational shaft from an outer peripheral surface of the rotational shaft. The thrust bearing can support an axial load of the thrust runner. The thrust bearing can include a bearing shell. The bearing shell can support the thrust bearing. The bearing shell includes a shell body and a shell cover. The shell body can have a cooling path through which a working fluid flows. The shell cover is coupled to cover one side of the shell body. The shell cover can have an injection hole communicating with the cooling path. The shell cover can form a fluid film by injecting the working fluid into the gap through the injection hole.

[0019] Through this, the thrust bearing can support the axial load of the thrust runner by forming a dynamic pressure through the fluid film. The cooling channel and the injection hole can spray the coolant not directly to the thrust bearing, but to the thrust runner, and then the reflected coolant can be supplied to the thrust bearing to mitigate the impact.

[0020] In one embodiment, the working fluid may be a refrigerant. This allows the thrust bearing to receive refrigerant from a condenser of the refrigeration cycle. The refrigerant may cool the thrust bearing.

[0021] In one embodiment, the thrust bearing includes a top foil and a bump foil. The top foil may be arranged to face the thrust runner with the gap therebetween. The bump foil may have a plurality of bump portions formed in a curved shape and a plurality of connecting portions connecting the plurality of bump portions. The bump foil may elastically support the top foil.

[0022] Through this, the thrust bearing can be implemented as a gas foil bearing.

[0023] In one embodiment, the shell cover may further include a bearing plate mounted on one side. One end of the top foil may be fixed to one side of the bearing plate, and the other end of the top foil may be a free end. The bump foil may be arranged between the bearing plate and the top foil.

[0024] Through this, the bearing plate can facilitate the coupling of the shell cover and the thrust bearing.

[0025] In one embodiment, the shell body may be formed in a cylindrical shape. The shell cover may be formed in a circular plate shape having the same diameter as the shell body. The shell cover may include a first surface disposed toward the thrust runner; and a second surface disposed toward the shell body. The thickness of the shell cover may be formed between the first surface and the second surface. The injection hole may be disposed radially inward of the shell cover. The injection hole may penetrate the thickness of the shell cover and be formed to be inclined radially outward of the rotational axis with respect to the axial direction of the rotational axis.

[0026] Through this, the refrigerant injected through the injection hole can smoothly move radially outward from the inner end of the thrust bearing by centrifugal force resulting from the rotation of the thrust runner.

[0027] In another embodiment, the injection hole may be formed to be inclined in the circumferential direction with respect to the radial direction of the shell cover.

[0028] Through this, the refrigerant injected through the injection hole can easily move along the rotational direction of the thrust runner.

[0029] In one embodiment, the first surface of the shell cover may be divided into N sections 360 degrees apart. Thrust bearings may be arranged in each of the N sections. One or more injection holes may be arranged in each section.

[0030] Through this, the injection hole can evenly distribute the flow rate of the coolant provided to the plurality of thrust bearings.

[0031] In one embodiment, the shell body may include an inner wall portion surrounding the rotational axis; an outer wall portion spaced radially outward from the inner wall portion; and a connecting wall connecting one end of the inner wall portion and the outer wall portion. The cooling channel may be formed between the inner wall portion, the outer wall portion, and the connecting wall. The cooling channel may extend circumferentially along the periphery of the inner wall portion.

[0032] Through this, the cooling channel can connect the plurality of injection holes in a circumferential direction.

[0033] In one embodiment, the shell cover may include a first surface facing the thrust runner and a second surface facing the shell body. The injection hole may penetrate the thickness of the shell cover formed between the first surface and the second surface. One side of the injection hole may be adjacent to the inner wall portion, and the other side of the injection hole may be disposed adjacent to the radially inner end portion of the thrust bearing.

[0034] Through this, the injection hole can smoothly supply the thrust bearing by centrifugal force from the inner end of the thrust runner toward the outer end.

[0035] In one embodiment, the shell body may include a flow path inlet formed radially through one side of the outer wall portion so that the working fluid flows into the cooling path; and a flow path outlet formed radially through the other side of the outer wall portion so that the working fluid flows out of the cooling path.

[0036] Through this, the shell body can facilitate the inflow and outflow of refrigerant into the cooling channel.

[0037] In one embodiment, the shell cover may include a first surface facing the thrust runner and a second surface facing the shell body. A thickness of the shell cover may be formed between the first surface and the second surface. A fixing groove for inserting and fixing one end of the top foil may be formed to extend radially within the thickness of the shell cover.

[0038] Through this, the fixing groove can easily fix the top foil of the thrust bearing.

[0039] In one embodiment, the fixing groove may be formed in a hook shape. This allows the fixing groove to fix the top foil with a simple structure without adhesive or welding.

[0040] In one embodiment, the shell cover may include a first surface facing the thrust runner; and a second surface facing the shell body. A thickness of the shell cover may be formed between the first surface and the second surface. A fixing pin for fixing the thrust bearing to the shell cover may protrude from the first surface toward the thrust runner. The thrust bearing may further include a mounting guide. The mounting guide may protrude from an outer peripheral portion of the bearing plate toward the fixing pin. The mounting guide may have a guide groove into which the fixing pin is slidably engaged.

[0041] Through this, the separable thrust bearing can be detachably coupled to the shell cover.

[0042] In one embodiment, the shell cover may further include a fixing groove. The fixing groove may be formed to be recessed from a first surface of the shell cover toward a second surface of the shell cover. The fixing pin may be coupled to the fixing groove.

[0043] Through this, the fixed pin can be easily coupled to the shell cover.

[0044] According to one embodiment of the present invention, a turbocompressor includes a housing. The turbocompressor includes a rotating shaft rotatably provided within the housing. The turbocompressor includes an impeller coupled to one end of the rotating shaft. The turbocompressor includes a motor for driving the impeller. The motor may include a rotor connected to the rotating shaft and a stator surrounding the rotor. The turbocompressor includes a thrust runner formed to protrude in a radial direction of the rotating shaft from an outer peripheral surface of the rotating shaft. The turbocompressor includes a thrust bearing and a bearing shell. The thrust bearing is arranged with a gap from the thrust runner. The thrust bearing can support an axial load of the thrust runner. The bearing shell can support the thrust bearing. The bearing shell includes: a shell body having a cooling passage through which a working fluid flows; And it may include a shell cover that is coupled to cover one side of the shell body, has an injection hole that communicates with the cooling channel, and forms a fluid film by injecting the working fluid into the gap through the injection hole.

[0045] Through this, the turbo compressor can supply working fluid to the thrust bearing through the cooling passage and the injection hole, as well as cool the thrust bearing.

[0046] In one embodiment, the turbocompressor may further include an impeller casing that accommodates the impeller and has a diffuser therein that converts velocity energy of the working fluid sucked by the impeller into pressure energy.

[0047] Through this, the impeller casing can compress the working fluid through the diffuser.

[0048] In one embodiment, the impeller may include a first impeller coupled to one end of the rotating shaft; and a second impeller coupled to the other end of the rotating shaft. The turbocompressor may further include a first journal bearing and a second journal bearing. The first journal bearing may be disposed between the thrust bearing and the rotor. The first journal bearing may support a radial load of one end of the rotating shaft. The second journal bearing may be disposed between the second impeller and the rotor. The second journal bearing may support a radial load of the other end of the rotating shaft.

[0049] Through this, the first journal bearing and the second journal bearing can limit the rotation axis from moving or rotating in the radial direction.

[0050] In one embodiment, the thrust runner may include a first surface facing the impeller and a second surface facing the motor. A thickness of the thrust runner may be formed between the first surface and the second surface of the thrust runner.

[0051] The thrust bearing may include a first thrust bearing arranged toward the first surface; a first bearing shell supporting the first thrust bearing; a second thrust bearing arranged toward the second surface; and a second bearing shell supporting the second thrust bearing.

[0052] Through this, the thrust bearing can not only support the axial load of the thrust runner in both directions, but can also be stably supported by the bearing shell.

[0053] In one embodiment, the turbocompressor may include at least one of a refrigerant inlet, a first liquid refrigerant prevention chamber, an inlet branch passage, a second liquid refrigerant prevention chamber, and an outlet branch passage. The refrigerant inlet may be formed to penetrate the housing in a radial direction. The refrigerant inlet may introduce refrigerant supplied from a condenser into an internal space of the housing. The first liquid refrigerant prevention chamber may be provided inside the housing. The first liquid refrigerant prevention chamber may be connected to the refrigerant inlet so as to be in communication with it. The first liquid refrigerant prevention chamber may be formed to have a volume larger than that of the refrigerant inlet. The inlet branch passage may be connected to the first liquid refrigerant prevention chamber and a passage inlet formed on one side of the shell body. The inlet branch passage may transfer the refrigerant to the cooling passage. The second liquid refrigerant prevention chamber may be provided inside the housing. The second liquid refrigerant prevention chamber may be arranged in an opposite direction to the first liquid refrigerant prevention chamber with respect to the rotation axis. The outlet branch path may be connected to a flow path outlet formed on the other side of the shell body and the second liquid refrigerant prevention chamber. The outlet branch path may cause the refrigerant to flow from the cooling path to the second liquid refrigerant prevention chamber.

[0054] Through this, the first liquid refrigerant prevention chamber can prevent the inflow of liquid refrigerant among the refrigerants flowing into the cooling channel. The second liquid refrigerant prevention chamber can prevent the outflow of liquid refrigerant among the refrigerants flowing out of the cooling channel.

[0055] In one embodiment, the turbocompressor may include a sealing portion and a bearing housing. The sealing portion may be coupled to one end of the housing. The sealing portion may accommodate and support the first bearing shell. The bearing housing may be arranged between the sealing portion and the transmission portion. The bearing housing may accommodate and support the second bearing shell.

[0056] The above inflow branch flow path may include a first inflow branch flow path and a second inflow branch flow path. The first inflow branch flow path may be provided on one side of the inside of the sealing portion. The first inflow branch flow path may connect one side of the first liquid refrigerant prevention chamber and the flow path inlet of the first bearing shell. The second inflow branch flow path may be provided on one side of the inside of the bearing housing. The second inflow branch flow path may connect the other side of the first liquid refrigerant prevention chamber and the flow path inlet of the second bearing shell.

[0057] The above-mentioned outflow branch path may include a first outflow branch path and a second outflow branch path. The first outflow branch path may be provided on the other inner side of the sealing portion. The first outflow branch path may connect the flow path outlet of the first bearing shell and one side of the second liquid refrigerant prevention chamber. The second outflow branch path may be provided on the other inner side of the bearing housing. The second outflow branch path may connect the flow path outlet of the second bearing shell and the other side of the second liquid refrigerant prevention chamber.

[0058] Through this, the turbocompressor can easily form first and second inlet branch passages in the sealing portion and the bearing housing, respectively. In addition, the first and second outlet branch passages can easily be formed inside the sealing portion and the bearing housing. In addition, the first bearing shell and the second bearing shell can be easily assembled inside the sealing portion and the bearing housing.

[0059] According to an embodiment of the present invention, the following effects can be achieved.

[0060] First, thrust bearings form cooling channels and cooling holes within the bearing shell. The bearing shell comprises a shell body and a shell cover. The shell cover is joined to cover one side of the shell body. A thrust bearing can be mounted on the shell cover.

[0061] The cooling channel is formed inside the shell body. The cooling hole is formed at a predetermined angle with respect to the axial direction on the radially inner side of the shell cover.

[0062] The refrigerant supplied from the condenser to the inside of the compressor housing is not directly sprayed onto the thrust bearing, but is indirectly sprayed onto the thrust bearing through the cooling passage and cooling holes formed inside the bearing shell.

[0063] For example, refrigerant is injected from the refrigerant passage through the injection holes onto one side of the thrust runner. As the high-pressure refrigerant hits one side of the thrust runner, the injection speed and injection pressure are reduced.

[0064] Additionally, the coolant reflected from one side of the thrust runner may flow radially inward of the gap between the thrust runner and the top foil of the thrust bearing.

[0065] The refrigerant introduced into the radially inner side of the above gap moves to the radially outer side of the gap due to centrifugal force resulting from the rotation of the thrust runner, thereby forming a fluid film.

[0066] In addition, the fluid film formed in the gap forms a dynamic pressure by friction with one surface of the thrust runner that rotates in the circumferential direction from the fixed portion, which is the starting point of the top foil, toward the free end, which is the end point of the top foil.

[0067] Through this, the thrust bearing can support the axial load of the thrust runner by the dynamic pressure of the fluid film.

[0068] Second, since the coolant is reflected on one surface of the thrust runner and then supplied to the gap between the thrust bearing and the thrust runner, the shock caused by the coolant being directly supplied to the bearing can be alleviated.

[0069] Third, heat is generated due to friction of the fluid film in the above gap.

[0070] The refrigerant injected through the cooling hole is relatively lower than the temperature of the fluid film.

[0071] Through this, the coolant supplied through the gap can cool the heat of the thrust bearing.

[0072] Fourth, the refrigerant supplied into the housing can be vaporized by moving to the liquid refrigerant prevention chamber through the radial communication passage inlet and expanding in volume. This prevents the liquid refrigerant from flowing into the thrust bearing.

[0073] Accordingly, the liquid refrigerant prevention chamber can solve the problem of lowering the bearing's support performance by blocking the inflow of liquid refrigerant and causing impact and damage to the fluid film due to the inflow of liquid refrigerant.

[0074] Fifth, the liquid refrigerant prevention chamber vaporizes the liquid refrigerant and absorbs the heat of the liquid refrigerant as heat of vaporization, thereby lowering the temperature of the refrigerant to be supplied to the thrust bearing, thereby improving the cooling performance of the thrust bearing.

[0075] Sixth, the first and second inlet branch channels extending radially from the radial inlet of the first bearing housing, the liquid refrigerant prevention chamber, and the cooling channel inside the shell body of the bearing shell each extend radially, so that the channel structure is simple and the flow resistance is minimized, thereby sufficiently securing the flow rate of the refrigerant.

[0076] Seventh, the injection holes formed in the shell cover of the bearing shell are formed at least once for each thrust bearing spaced at equal intervals along the circumferential direction, so that they can simultaneously supply air to multiple thrust bearings, thereby efficiently cooling the thrust bearings.

[0077] Eighth, the injection hole formed in the shell cover of the bare shell is formed to be inclined toward the inner end of the thrust bearing, so that the refrigerant can be smoothly supplied by the centrifugal force generated by the rotation of the thrust runner.

[0078] FIG. 1 is a conceptual diagram showing a cross-section of a turbocompressor according to one embodiment of the present invention.

[0079] Figure 2 is a conceptual diagram showing the components of the turbo compressor in Figure 1 in an exploded view.

[0080] Figure 3 is a conceptual diagram showing the path through which the working fluid is supplied to the thrust bearing by enlarging III in Figure 1.

[0081] FIG. 4 is a conceptual diagram showing an axial view of an integral thrust bearing according to one embodiment of FIG. 3.

[0082] Fig. 5 is a cross-sectional view taken along line VV in Fig. 4, and is a conceptual diagram showing the configuration of a thrust bearing.

[0083] Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 4, and is a conceptual diagram showing the working fluid being injected into the thrust bearing through the injection hole.

[0084] Figure 7 is a conceptual diagram showing the fixed end of the top foil in Figure 4 being fixed to the fixed groove of the bearing shell.

[0085] Figure 8 is a conceptual diagram showing that the refrigerant is sprayed radially through the injection hole in Figure 4.

[0086] FIG. 9 is a conceptual diagram showing an axial view of a separable thrust bearing according to another embodiment of FIG. 3.

[0087] Fig. 10 is a cross-sectional view taken along XX in Fig. 9, and is a conceptual diagram showing the working fluid being sprayed into the thrust bearing through the cooling hole.

[0088] Figure 11 is a conceptual diagram showing that the coolant in Figure 4 is sprayed obliquely toward the center of the thrust bearing in the radial direction through the injection hole.

[0089] Figure 12 is a conceptual diagram showing a plurality of injection holes formed for each thrust bearing in Figure 4.

[0090] Hereinafter, a thrust bearing and a turbo compressor equipped therewith according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0091] In the following description, descriptions of some components may be omitted to clarify the features of the present invention.

[0092] 1. Definition of Terms

[0093] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0094] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0095] As used herein, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0096] The term “turbocompressor” used in the following description can be understood as a concept meaning a device that compresses gas such as refrigerant by rotating an impeller using power such as an electric motor.

[0097] As used herein, “radial” or “radial” means a shape that extends out in all directions from a central point like spokes of a wheel.

[0098] “Axial” as used in the following description means the longitudinal direction of the axis of rotation.

[0099] As used in the following description, “radial direction” means the longitudinal direction of a line segment from the center of a circle or cylinder to a point on the circumference (circumference).

[0100] As used in the following description, “circumferential” means the direction of the circumference of a circle.

[0101] 2. Description of the configuration of a turbo compressor according to one embodiment of the present invention.

[0102] FIG. 1 is a conceptual diagram showing a cross-section of a turbocompressor according to one embodiment of the present invention.

[0103] Figure 2 is a conceptual diagram showing the components of the turbo compressor in Figure 1 in an exploded view.

[0104] Figure 3 is a conceptual diagram showing the path through which the operating fluid is supplied to the thrust bearings (130a, 130b) by enlarging III in Figure 1.

[0105] Hereinafter, each component of a turbo compressor according to an embodiment of the present invention will be described with reference to the attached drawings.

[0106] A turbo compressor according to the present invention includes at least one of a housing (100), an electric motor (120), a rotating shaft (118), and an impeller (128a, 128b).

[0107] (1) Components of a turbo compressor

[0108] The housing (100) may be formed in a cylindrical shape. The housing (100) may form the exterior or outer periphery of the turbocompressor.

[0109] A receiving space is formed inside the housing (100) to receive the electric part (120).

[0110] A motor support portion is formed on the inner surface of the housing (100). A stator core (122), which will be described later, can be press-fitted and joined to the motor support portion. One end of the motor support portion can be formed to be stepped in the radial direction of the housing (100).

[0111] Through this, the stator core (122) can be restricted from moving axially while being supported at one end of the motor support.

[0112] The housing (100) extends in the longitudinal or axial direction of the housing (100). Both ends of the housing (100) are formed to be open in the axial direction.

[0113] An impeller casing (102a, 102b) to be described later can be coupled to both ends of the housing (100).

[0114] The rotation axis (118) extends axially. The rotation axis (118) can be arranged to axially cross the radial center of the housing (100).

[0115] The electric motor (120) includes a stator (121) and a rotor (124). The stator (121) has a stator core (122) and a stator coil (123). The stator core (122) can be formed into a cylindrical shape by laminating and bonding a plurality of electrical steel plates.

[0116] The stator core (122) may be formed with a plurality of teeth protruding radially inward toward the rotation axis (118) on the inside of the stator core (122). A plurality of slots may be formed between the plurality of teeth. The plurality of teeth and the plurality of slots may be alternately arranged in the circumferential direction of the stator core (122) and spaced apart from each other in the circumferential direction.

[0117] The stator coil (123) is wound on the stator core (122) through a slot.

[0118] When power is applied to the stator coil (123), a magnetic field is generated around the stator coil (123).

[0119] The rotor (124) is placed inside the stator (121). The rotor (124) is placed so as to be spaced apart from the stator (121) by an air gap. The rotor (124) is mounted on a rotational shaft (118) so as to be rotatable with respect to the stator (121).

[0120] The rotor (124) may be configured to include a rotor core (125) and a permanent magnet (126). The rotor core (125) may be rotatably mounted together with the rotation shaft (118) or may be omitted. If the rotor core (125) is omitted, the permanent magnet (126) may be mounted on the rotation shaft (118). In this embodiment, the rotor core (125) is shown to be rotatably mounted together with the rotation shaft (118).

[0121] The permanent magnet (126) may be accommodated inside the rotor core (125) or mounted on the outer surface of the rotor core (125). When the permanent magnet (126) is accommodated inside the rotor core (125), a plurality of magnet accommodation holes may be formed to penetrate axially inside the rotor core (125).

[0122] In this embodiment, a plurality of permanent magnets (126) are shown mounted on the outer surface of the rotor core (125). The plurality of permanent magnets (126) can be arranged spaced apart from each other in the circumferential direction along the outer surface of the rotor core (125).

[0123] The permanent magnet (126) can extend axially. The permanent magnet (126) can extend radially. The radially inner end of the permanent magnet (126) can be contactably coupled to the outer surface of the rotation shaft (118). The radially outer end of the permanent magnet (126) can be contactably coupled to the inner surface of the rotor core (125).

[0124] A rotor support (1181) is formed at the center of the rotation shaft (118). The rotor support (1181) may have the same length as the length of the permanent magnet (126). The rotor support (1181) may have the same length as the length of the rotor core (125).

[0125] A permanent magnet (126) is mounted on the rotor core (125) and can be supported by the rotor core (125).

[0126] A bearing support portion may be provided on both sides of the rotation shaft (118) with the rotor support portion (1181) of the rotation shaft (118) interposed therebetween. The bearing support portion may be composed of a first bearing support portion (1182a) and a second bearing support portion (1182b). The first bearing support portion (1182a) may extend axially from one end of the magnet support portion.

[0127] The second bearing support (1182b) can extend axially from the other end of the magnet support.

[0128] The diameters of the first bearing support (1182a) and the second bearing support (1182b) can each be formed smaller than the diameter of the magnet support.

[0129] A plurality of end rings (127a, 127b) can be respectively coupled to both ends of the rotor core (125). The end rings (127a, 127b) can be mounted and coupled to the rotation shaft (118).

[0130] The end ring (127a, 127b) may be composed of a first end ring (127a) and a second end ring (127b).

[0131] The first end ring (127a) can be mounted and coupled to one end of the first bearing support member (1182a). The first end ring (127a) can be positioned to face one axial end of the permanent magnet (126). In this way, the first end ring (127a) can restrict the permanent magnet (126) from axially deviating from the magnet support member.

[0132] The second end ring (127b) can be mounted and connected to one end of the second bearing support member (1182b). The second end ring (127b) can be positioned to face the other axial end of the permanent magnet (126). In this way, the second end ring (127b) can limit the permanent magnet (126) from axially deviating from the magnet support member.

[0133] The rotation shaft (118) is configured to rotate together with the rotor (124) and transmit rotational force to the impeller (128a, 128b) described later.

[0134] The impeller (128a, 128b) is configured to suck in a working fluid such as a refrigerant. The impeller (128a, 128b) may be configured to include a hub (1281) and a plurality of blades (1283).

[0135] A through hole is provided axially to allow a rotation shaft (118) to pass through the inside of the hub (1281). The hub (1281) may be formed in a cone shape.

[0136] The outer surface of the hub (1281) may be formed to be inclined with respect to the axial direction. The diameter of the hub (1281) may be formed to increase from the upstream side to the downstream side of the hub (1281) with respect to the suction direction of the working fluid.

[0137] The blades (1283) may be formed to protrude along a spiral from the outer surface of the hub (1281). A plurality of blades (1283) are arranged to be spaced apart from each other in the circumferential direction of the hub (1281).

[0138] The impeller (128a, 128b) can be configured to discharge the working fluid sucked in the axial direction in the radial direction of the impeller (128a, 128b).

[0139] The impellers (128a, 128b) may be configured as a first impeller (128a) to an Nth impeller depending on the compression process of the refrigerant. In this embodiment, the first impeller (128a) and the second impeller (128b) are shown. The first impeller (128a) may be referred to as a single-stage impeller. The second impeller (128b) may be referred to as a two-stage impeller.

[0140] Unless the first impeller (128a) and the second impeller (128b) are separately distinguished in this specification, the description of the configuration of the impellers (128a, 128b) can be applied to the first impeller (128a) and the second impeller (128b).

[0141] The working fluid, such as refrigerant and / or air, may be compressed in one stage in the first impeller (128a) and then introduced into the second impeller (128b) for two-stage compression.

[0142] According to this configuration, the turbo compressor can compress the refrigerant in multiple stages depending on the number of impellers (128a, 128b). In this embodiment, a two-stage compressor is shown.

[0143] A first impeller support (1183a) and a second impeller support (1183b) may be provided at both ends of the rotation shaft (118).

[0144] The first impeller support (1183a) has a diameter smaller than the diameter of the first bearing support (1182a) of the rotation shaft (118). The first impeller support (1183a) may be formed to protrude axially from one end of the rotation shaft (118). The first impeller support (1183a) may be press-fitted into the inside of the hub (1281) of the first impeller (128a).

[0145] The second impeller support (1183b) has a diameter smaller than the diameter of the second bearing support (1182b) of the rotation shaft (118). The second impeller support (1183b) may be formed to protrude axially from the other end of the rotation shaft (118). The second impeller support (1183b) may be press-fitted into the inside of the hub (1281) of the second impeller (128b).

[0146] The impeller casing (102a, 102b) may be configured to include a first impeller casing (102a) and a second impeller casing (102b). The first impeller casing (102a) may be coupled to one side of the housing (100). The downstream end of the first impeller casing (102a) with respect to the suction direction of the working fluid may be configured to be covered by a first sealing portion (108a) to be described later. The first sealing portion (108a) may be accommodated on one side of the housing (100) together with a first bearing housing (110a) to be described later.

[0147] A second impeller casing (102b) may be coupled to the other side of the housing (100). The downstream end of the second impeller casing (102b) with respect to the suction direction of the working fluid may be configured to be covered by a second sealing portion (108b) to be described later. The second sealing portion (108b) may be accommodated on the other side of the housing (100) together with a second bearing housing (110b) to be described later.

[0148] The configuration of the impeller casing (102a, 102b) described below can be applied to the first impeller casing (102a) and the second impeller casing (102b) unless otherwise specified.

[0149] The impeller casing (102a, 102b) may be configured to include a suction portion (103a, 103b) and a diffuser casing (104a, 104b).

[0150] The suction portions (103a, 103b) may be formed in a cylindrical shape. The suction portions (103a, 103b) may extend axially. The suction portions (103a, 103b) may extend circumferentially. A suction port (105a, 105b) may be formed on the inside of the suction portions (103a, 103b).

[0151] The diffuser casing (104a, 104b) extends radially outward from the downstream end of the suction portion (103a, 103b) with respect to the flow direction of the working fluid. The diffuser casing (104a, 104b) may extend along the circumferential direction. The suction portion (103a, 103b) and the diffuser casing (104a, 104b) may be formed integrally with each other.

[0152] The impeller casing (102a, 102b) includes an inlet (105a, 105b), a diffuser (107a, 107b), and an outlet (106a, 106b). The inlet (105a, 105b) is formed to penetrate axially through the center of the impeller casing (102a, 102b). An impeller (128a, 128b) can be accommodated inside the inlet (105a, 105b).

[0153] The diameter of the suction ports (105a, 105b) may be formed to decrease from the upstream side to the downstream side based on the suction direction of the working fluid. Accordingly, the flow rate of the refrigerant sucked through the suction ports (105a, 105b) may increase.

[0154] The discharge ports (106a, 106b) may be provided on the outer periphery of the impeller casing (102a, 102b). The discharge ports (106a, 106b) may extend radially from the diffuser (107a, 107b) to be described later. The discharge pipes (116a, 116b) may be formed to protrude outward from the outer periphery of the impeller casing (102a, 102b).

[0155] One side of the discharge pipe (116a, 116b) is connected to the discharge port (106a, 106b). The other side of the discharge pipe (116a, 116b) can be connected to the outside of the impeller casing (102a, 102b).

[0156] The discharge pipe (116a, 116b) may be composed of a first discharge pipe (116a) and a second discharge pipe (116b). The first discharge pipe (116a) may be connected to the discharge port (106a, 106b) of the first impeller casing (102a).

[0157] One side of the second discharge pipe (116b) can be connected to the discharge port (106a, 106b) of the second impeller casing (102b). The other side of the second discharge pipe (116b) can be connected to the condenser and the refrigerant inlet, so that the two-stage compressed refrigerant can be delivered to the condenser.

[0158] The other side of the first discharge pipe (116a) can be connected to the suction port (105a, 105b) of the second impeller casing (102b). The middle part extending from one side to the other side of the first discharge pipe (116a) can be connected to the refrigerant discharge pipe (149) of the housing (100) to be described later.

[0159] The diffuser (107a, 107b) may be formed to be axially recessed in the downstream end surface of the diffuser casing (104a, 104b) based on the flow direction of the working fluid sucked into the impeller (128a, 128b). The diffuser (107a, 107b) is formed on the inside of the diffuser casing (104a, 104b). The diffuser (107a, 107b) is arranged between the suction port (105a, 105b) and the discharge port (106a, 106b).

[0160] The diffusers (107a, 107b) may be formed to extend in a spiral direction from the intake ports (105a, 105b). The diffusers (107a, 107b) are connected to the discharge ports (106a, 106b). The diffusers (107a, 107b) are formed so that the flow path size increases from the intake ports (105a, 105b) to the discharge ports (106a, 106b).

[0161] According to this configuration, the working fluid sucked in by the rotation of the impeller (128a, 128b) increases in pressure as it passes through the diffuser (107a, 107b). The diffuser (107a, 107b) can increase the pressure of the refrigerant by converting the kinetic energy of the working fluid sucked in by the impeller (128a, 128b) into pressure energy.

[0162] The discharge port (106a, 106b) of the first impeller casing (102a) can be connected to the suction port (105a, 105b) of the second impeller casing (102b). Through this, the working fluid can be compressed by the first diffuser (107a) of the first impeller casing (102a) and then sucked into the second diffuser (107b) of the second impeller casing (102b) to be recompressed.

[0163] In order to prevent the refrigerant compressed by the diffuser (107a, 107b) from flowing back or leaking to the impeller (128a, 128b), a sealing portion (108a, 108b) may be provided between the downstream end of the impeller (128a, 128b) and the bearing housing to be described later.

[0164] A sleeve (1282) may be further provided on the hub (1281) of the impeller (128a, 128b). The sleeve (1282) may extend axially from one end of the hub (1281). The sleeve (1282) may be provided on the downstream end of the hub (1281) based on the flow direction of the working fluid sucked by the impeller (128a, 128b).

[0165] The sleeve (1282) may be formed in a cylindrical shape.

[0166] The sleeve (1282) is configured to surround the impeller support (1183a, 1183b) of the rotation shaft (118). The sleeve (1282) is coupled to the impeller support (1183a, 1183b). Through this, the sleeve (1282) can rotate together with the impeller support (1183a, 1183b).

[0167] A penetration portion is formed to penetrate axially through the radially inner end of the sealing portion (108a, 108b). The impeller support portion (1183a, 1183b) of the rotating shaft (118) and the sleeve (1282) of the hub (1281) can penetrate the penetration portion. The penetration portion can be arranged to be radially spaced apart from the outer surface of the sleeve (1282).

[0168] A plurality of sealing projections (109) are formed to protrude radially inwardly toward the sleeve (1282) of the impeller (128a, 128b) at the penetration portion of the sealing portion (108a, 108b). The plurality of sealing projections (109) may be arranged to be spaced apart from each other in the axial direction.

[0169] A plurality of sealing projections (109) can be arranged radially spaced apart from the outer surface of the sleeve (1282).

[0170] Through this, the plurality of sealing projections (109) can seal the gap (gap) between the sleeve (1282) of the impeller (128a, 128b) and the radially inner end of the sealing portion (108a, 108b).

[0171] The sealing portions (108a, 108b) may include a first sealing portion (108a) and a second sealing portion (108b). The first sealing portion (108a) may be arranged between the first impeller (128a) and the first bearing housing (110a). The second sealing portion (108b) may be arranged between the second impeller (128b) and the second bearing housing (110b).

[0172] Both sides of the rotation shaft (118) may be supported by bearings. The bearings may include journal bearings (129a, 129b) and thrust bearings (130a, 130b).

[0173] Journal bearings (129a, 129b) may be implemented as any one of a ball bearing, a roller bearing, a rolling bearing, or a fluid bearing, such as a gas foil bearing. In the present embodiment, journal bearings (129a, 129b) may be implemented as a gas foil bearing.

[0174] Journal bearings (129a, 129b) are configured to support the radial load of the rotation shaft (118). The journal bearings (129a, 129b) may be formed in a cylindrical shape. The journal bearings (129a, 129b) are configured to surround the bearing support portion of the rotation shaft (118).

[0175] A gap may be formed between the inner surface of the journal bearing (129a, 129b) and the outer surface of the bearing support portion of the rotary shaft (118). A refrigerant, which is a working fluid, may flow through the gap to form a fluid film.

[0176] Through this, the journal bearings (129a, 129b) can support the radial load of the rotating shaft (118) by forming a dynamic pressure through the fluid film.

[0177] Additionally, the journal bearings (129a, 129b) can limit the rotation axis (118) from moving radially.

[0178] The journal bearings (129a, 129b) may be composed of a first journal bearing (129a) and a second journal bearing (129b). The first journal bearing (129a) is configured to support one side of the rotation shaft (118). The first journal bearing (129a) may be arranged between the first impeller (128a) and the electric motor (120). The first journal bearing (129a) may be arranged between the first impeller (128a) and the rotor (124).

[0179] The second journal bearing (129b) is configured to support the other side of the rotation shaft (118). The second journal bearing (129b) may be arranged between the second impeller (128b) and the electric motor (120). The second journal bearing (129b) may be arranged between the second impeller (128b) and the rotor (124).

[0180] The bearing housing is configured to support the bearing. The bearing housing may include an axial extension portion (113a, 113b) and a radial extension portion (114a, 114b).

[0181] The axial extension portions (113a, 113b) extend in the axial direction. The axial extension portions (113a, 113b) may extend along the circumferential direction. The axial extension portions (113a, 113b) may be formed in a cylindrical shape. The axial extension portions (113a, 113b) are formed to surround the rotational shaft (118). A journal bearing (129a, 129b) may be mounted on the inner circumferential surface of the axial extension portions (113a, 113b).

[0182] The radial extension portions (114a, 114b) extend radially from one end of the axial extension portions (113a, 113b). The radial extension portions (114a, 114b) may extend in the circumferential direction. A thrust bearing (130a, 130b), which will be described later, may be mounted on the inside of the radial extension portions (114a, 114b).

[0183] The bearing housing includes a first bearing housing (110a) and a second bearing housing (110b).

[0184] The first bearing housing (110a) can be placed between the first sealing portion (108a) and the electric portion (120). The first bearing housing (110a) can support the first journal bearing (129a) and the second thrust bearing (130b) to be described later.

[0185] The second bearing housing (110b) can be arranged between the second sealing portion (108b) and the power unit (120). The axial extension portion (113a, 113b) of the second bearing housing (110b) can support the second journal bearing (129b).

[0186] A unilateral axial load is applied to the rotation shaft (118). The unilateral axial load refers to an axial force directed from the second impeller (128b) toward the first impeller (128a).

[0187] When a two-stage compression turbo compressor is operated, the pressure sucked into the second impeller (128b) is the pressure of the working fluid compressed primarily by the first impeller (128a) and the first diffuser (107a), so the pressure sucked into the second impeller (128b) is greater than the pressure sucked into the first impeller (128a).

[0188] Due to the pressure difference between the working fluid sucked into the first impeller (128a) and the working fluid sucked into the second impeller (128b), a unilateral axial load can be applied from the second impeller (128b) toward the first impeller (128a).

[0189] A thrust runner (119) is formed to protrude radially outward from the rotation shaft (118). The thrust runner (119) can extend circumferentially along the circumference of the rotation shaft (118). Through this, the thrust runner (119) can transmit an axial load to the thrust bearings (130a, 130b).

[0190] The thrust runner (119) may include a first surface (1191), a second surface (1192), and an outer surface (1193). The first surface (1191) of the thrust runner (119) is a plane arranged toward the first impeller (128a). The second surface (1192) of the thrust runner (119) is a plane arranged toward the opposite direction to the first surface (1191). The outer surface (1193) of the thrust runner (119) is a curved surface connecting the first surface (1191) and the second surface (1192). The thickness (1194) of the thrust runner (119) may be formed between the first surface (1191) and the second surface (1192). A unilateral axial load can be applied to the first surface (1191) of the thrust runner (119).

[0191] In this embodiment, the thrust bearings (130a, 130b) may be configured to include a first thrust bearing (130a) and a second thrust bearing (130b). However, the second thrust bearing (130b) may be omitted as needed.

[0192] The first thrust bearing (130a) may be mounted on the first sealing portion (108a). The first sealing portion (108a) may include a first surface, a second surface, and an outer circumferential surface. The first surface of the first sealing portion (108a) may be arranged toward one surface of the impeller casing (102a, 102b). The second surface of the first sealing portion (108a) may be arranged toward the radially extended portion (114a, 114b) of the first bearing housing (110a).

[0193] The thickness of the sealing portion (108a, 108b) can be formed between the first surface and the second surface of the first sealing portion (108a). The outer surface of the first sealing portion (108a) is formed to connect the first surface and the second surface of the first sealing portion (108a). The first surface and the second surface of the first sealing portion (108a) are flat. The outer surface of the first sealing portion (108a) is a circular curved surface.

[0194] The first bearing mounting portion (111a) may be formed to be recessed from the second surface of the first sealing portion (108a) toward the first surface of the first sealing portion (108a). The first bearing mounting portion (111a) may extend in the circumferential direction of the first sealing portion (108a). The inner circumferential diameter of the first bearing mounting portion (111a) is formed to correspond to the diameter of the first thrust bearing (130a).

[0195] Through this, the first thrust bearing (130a) can be press-fitted into the first bearing mounting portion (111a).

[0196] The second thrust bearing (130b) may be mounted on the first bearing housing (110a). The first bearing housing (110a) may include a first surface, a second surface, and an outer circumferential surface. The first surface of the first bearing housing (110a) (radially extended portion (114a, 114b)) may be arranged toward the first sealing portion (108a).

[0197] The second surface of the first bearing housing (110a) may be arranged toward the power unit (120). The second surface of the first bearing housing (110a) may be connected to an axial extension portion (113a, 113b). A curved portion may be formed at a preset curvature at the inner end of the second surface of the first bearing housing (110a).

[0198] The thickness of the first bearing housing (110a) is formed between the first surface and the second surface of the first bearing housing (110a). The first surface and the second surface of the first bearing housing (110a) are each flat.

[0199] The outer surface of the first bearing housing (110a) is formed to connect the first surface and the second surface of the first bearing housing (110a). The outer surface of the first bearing housing (110a) can form a circular curved surface.

[0200] The second bearing mounting portion (111b) may be formed to be recessed from the first surface of the first bearing housing (110a) toward the second surface of the first bearing housing (110a). The second bearing mounting portion (111b) may extend in the circumferential direction of the first bearing housing (110a).

[0201] The second bearing mounting portion (111b) may be formed in a cylindrical shape. The inner circumferential diameter of the second bearing mounting portion (111b) is formed to correspond to the diameter of the second thrust bearing (130b).

[0202] Through this, the second thrust bearing (130b) can be press-fitted into the second bearing mounting portion (111b).

[0203] The thrust runner (119) can be accommodated in the second bearing mounting portion (111b).

[0204] The first sealing portion (108a) and the first bearing housing (110a) can be arranged axially and continuously between the first impeller (128a) and the electric motor (120). The second surface of the first sealing portion (108a) and the first surface of the first bearing housing (110a) can be in surface contact with each other.

[0205] The first impeller (128a) and the second impeller (128b) are arranged at both ends of the rotation shaft (118). A plurality of thrust bearings (130a, 130b) and a plurality of journal bearings (129a, 129b) may be arranged between the first impeller (128a) and the second impeller (128b). The first thrust bearing (130a), the second thrust bearing (130b), the first journal bearing (129a), and the second journal bearing (129b) may be arranged in sequence along the axial direction from the first impeller (128a) toward the second impeller (128b).

[0206] Through this, the length of the rotation shaft (118) can be shortened. In addition, the length of the turbo compressor can be shortened, thereby miniaturizing it.

[0207] 3. Description of the configuration of an integral thrust bearing (130a, 130b) according to one embodiment of the present invention.

[0208] FIG. 4 is a conceptual diagram showing an axial view of an integral thrust bearing (130a, 130b) according to one embodiment of FIG. 3.

[0209] Fig. 5 is a cross-sectional view taken along line VV in Fig. 4, and is a conceptual diagram showing the configuration of thrust bearings (130a, 130b).

[0210] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4, and is a conceptual diagram showing the working fluid being injected into the thrust bearings (130a, 130b) through the injection hole (139).

[0211] Figure 7 is a conceptual diagram showing the fixed end of the top foil (131) in Figure 4 being fixed to the fixed groove (140) of the bearing shell (134a, 134b).

[0212] Figure 8 is a conceptual diagram showing that the refrigerant is sprayed radially through the injection hole (139) in Figure 4.

[0213] The thrust bearing (130a, 130b) can be implemented with at least one gas foil bearing.

[0214] The thrust bearing (130a, 130b) may include a top foil (131) and a bump foil (132). The thrust bearing (130a, 130b) may further include a bearing plate (133).

[0215] The top foil (131) is configured to cover the bump foil (132). The top foil (131) can form the outer appearance of the thrust bearing (130a, 130b). The top foil (131) can form one axial surface of the thrust bearing (130a, 130b).

[0216] The first surface of the top foil (131) may be arranged toward the first surface of the thrust runner (119). The second surface of the top foil (131) may be arranged toward the bump foil (132). The thickness of the top foil (131) may be formed between the first surface and the second surface of the top foil (131).

[0217] The top foil (131) may include a fixed portion (1311), an inclined portion (1312), and a flat portion (1313).

[0218] The fixed part (1311) can be fixed to the bearing plate (133) to be described later or the bearing shell (134a, 134b) to be described later by welding or an adhesive or other adhesive means.

[0219] The inclined portion (1312) extends from the fixed portion (1311) toward the flat portion (1313). The inclined portion (1312) is configured to connect the fixed portion (1311) and the flat portion (1313). The inclined portion (1312) is formed to be inclined at a preset angle with respect to the bearing plate (133) or the bearing shell (134a, 134b).

[0220] The flat portion (1313) can be in contact with the bump foil (132) to be described later. The thickness of the flat portion (1313) can be formed between the first and second surfaces of the flat portion (1313). The first and second surfaces of the flat portion (1313) each form a flat surface.

[0221] The first surface of the flat portion (1313) may be arranged toward the thrust runner (119). The second surface of the flat portion (1313) may be arranged toward the bump foil (132). The second surface of the flat portion (1313) may be arranged parallel to the first surface of the thrust runner (119).

[0222] The fixed portion (1311), inclined portion (1312), and flat portion (1313) of the top foil (131) may have the same thickness.

[0223] The bump foil (132) may be configured to include a plurality of bump portions (1321) and a plurality of connecting portions (1322).

[0224] The bump portion (1321) may be formed in a semicircular or arc shape. However, the bump portion (1321) is not limited to the above shape.

[0225] The bump portion (1321) has a curved surface with a preset curvature. The thickness of the bump portion (1321) is formed between the first surface and the second surface of the bump portion (1321).

[0226] The thickness of the bump portion (1321) may be formed to be constant. The first surface of the bump portion (1321) may be arranged toward the top foil (131). The second surface of the bump portion (1321) may be arranged toward the opposite direction to the first surface of the bump portion (1321). The second surface of the bump portion (1321) may be arranged toward the bearing plate (133) or bearing shell (134a, 134b) described later.

[0227] A portion of the first surface of the bump portion (1321) can be in contact with the top foil (131). The bump portion (1321) is formed to have elasticity. For example, a portion of the bump portion (1321) can be in contact with the top foil (131) and receive an axial load.

[0228] A portion of the bump portion (1321) can be elastically deformed by an axial load. When the axial load is released, a portion of the bump portion (1321) can be restored to its original position and maintain its original shape. Through this, the bump foil (132) can elastically support the top foil (131) by utilizing the elastic force of the bump portion (1321).

[0229] One area of ​​the first surface of the bump portion (1321) may be positioned at the highest height with respect to the connection portion (1322) described later. Another area of ​​the first surface of the bump portion (1321) may be positioned closer to the connection portion (1322) than the one area of ​​the connection portion (1322).

[0230] The connecting portion (1322) is configured to connect one end of two bump portions (1321) adjacent to each other in the longitudinal direction of the bump foil (132). The connecting portion (1322) may be formed in a flat shape. The thickness of the connecting portion (1322) is formed between the first surface and the second surface of the connecting portion (1322).

[0231] The thickness of the connecting portion (1322) can be formed to be constant. The thicknesses of the bump portion (1321) and the connecting portion (1322) can be formed to be the same.

[0232] The first surface of the connecting portion (1322) may be arranged toward the top foil (131). The second surface of the connecting portion (1322) may be arranged in a direction opposite to the first surface of the connecting portion (1322). The second surface of the connecting portion (1322) may be arranged toward the bearing plate (133) or the bearing shell (134a, 134b).

[0233] The second surface of the connecting portion (1322) can be fixed to the bearing plate (133) or bearing shell (134a, 134b) described later by a fixing means such as an adhesive or welding. Through this, the bump foil (132) can be fixed to the bearing plate (133) or bearing shell (134a, 134b).

[0234] The bearing plate (133) may be formed in a flat shape. The thickness of the bearing plate (133) may be formed between the first surface and the second surface of the bearing plate (133). The first surface of the bearing plate (133) may be arranged toward the bump foil (132). The second surface of the bearing plate (133) may be arranged toward the bearing shell (134a, 134b).

[0235] The bump foil (132) may extend circumferentially along the circumference of the rotation axis (118). The bump foil (132) may have a radial width. The bump foil (132) may be arranged in multiple pieces spaced apart in the circumferential sections divided into N equal parts (N is a natural number greater than or equal to 2) of a 360-degree circle. In the present embodiment, the bump foil (132) may be arranged spaced apart in the sections divided into six equal parts.

[0236] Bump foils (132) divide the radius of the bearing mounting portion of the bearing shell (134a, 134b) into M equal parts (M is a natural number greater than or equal to 2), and can be arranged in multiple rows spaced apart in the divided radial section.

[0237] The multiple rows of bump foils (132) can be composed of the first to Mth rows of bump foils (132) from the radially inner side to the outer side of the bearing shell (134a, 134b).

[0238] A plurality of bump portions (1321) and a plurality of connecting portions (1322) may be arranged alternately in the circumferential direction. Each bump foil (132) may be configured by connecting a plurality of bump portions (1321) with a plurality of connecting portions (1322). At least one point or one area of ​​the bump foil (132) may be fixed to the bearing plate (133) or the bearing shell (134a, 134b).

[0239] The top foil (131) may be configured to cover a plurality of bump foils (132). For example, the top foil (131) may extend in the circumferential direction of the bearing shell (134a, 134b). The top foil (131) may extend along the radial direction of the bearing shell (134a, 134b).

[0240] The top foil (131) divides a 360-degree circle into N equal parts (N is a natural number greater than or equal to 2), and can be arranged in multiple pieces spaced apart in the divided circumferential sections. In the present embodiment, the top foil (131) can be arranged spaced apart in the circumferential sections divided into 6 equal parts.

[0241] In this embodiment, the thrust bearing (130a, 130b) may further include a bearing shell (134a, 134b).

[0242] A bearing mounting portion may be formed to be sunken into one surface of the bearing shell (134a, 134b). The thrust bearing (130a, 130b) may be mounted and supported on the bearing mounting portion.

[0243] The bearing shell (134a, 134b) may be composed of a shell body (135a, 135b) and a shell cover (138a, 138b). The shell body (135a, 135b) may be formed in a cylindrical shape.

[0244] An axial penetration portion (1352) is formed to penetrate axially at the center of the shell body (135a, 135b). Through this, the rotational shaft (118) can penetrate the axial penetration portion (1352). The shell body (135a, 135b) may be configured to include an inner wall portion (1351), an outer wall portion (1353), and a connecting wall (1355).

[0245] The inner wall portion (1351) can form an axial penetration portion (1352) of the shell body (135a, 135b). The inner wall portion (1351) can extend in the circumferential direction to surround the rotation axis (118). The inner wall portion (1351) can be arranged to be spaced apart from the rotation axis (118) with a gap.

[0246] The outer wall portion (1353) can form the outer surface of the shell body (135a, 135b). The outer wall portion (1353) can be arranged radially outside the inner wall portion (1351). The outer wall portion (1353) and the inner wall portion (1351) are arranged to be spaced apart from each other in the radial direction.

[0247] The inner wall portion (1351) may be formed in a cylindrical shape. The outer wall portion (1353) may be formed in a cylindrical shape. The diameter of the outer wall portion (1353) is larger than the diameter of the inner wall portion (1351).

[0248] One end of the outer wall portion (1353) and one end of the inner wall portion (1351) may be connected by a connecting wall (1355). The connecting wall (1355) extends radially. The connecting wall (1355) may extend circumferentially along the perimeter of the inner wall portion (1351).

[0249] Cooling channels (136a, 136b) are formed inside the shell body (135a, 135b). The outer wall portion (1353), inner wall portion (1351), and connecting wall (1355) can form cooling channels (136a, 136b).

[0250] An opening may be formed at the other end of the outer wall portion (1353) and the other end of the inner wall portion (1351) facing in the opposite direction to the connecting wall (1355). The opening may be axially open toward the shell cover (138a, 138b).

[0251] A flow path inlet (137a) may be formed to penetrate radially on one side of the outer wall (1353). The flow path inlet (137a) is connected to the cooling paths (136a, 136b). The flow path inlet (137a) may be arranged on the upper side of the shell body (135a, 135b).

[0252] A flow outlet (137b) may be formed to penetrate radially on the other side of the outer wall portion (1353). The flow outlet (137b) is connected to the cooling flow path (136a, 136b). The flow outlet (137b) may be arranged on the lower side of the shell body (135a, 135b).

[0253] A thickness (1383) of the shell cover (138a, 138b) is formed between the first surface (1381) of the shell cover (138a, 138b) and the second surface of the shell cover (138a, 138b). The first surface (1381) of the shell cover (138a, 138b) is arranged toward the thrust runner (119). The second surface of the shell cover (138a, 138b) is arranged toward the shell body (135a, 135b). The shell cover (138a, 138b) may be formed in a circular plate shape.

[0254] The shell cover (138a, 138b) is formed to cover the opening of the shell body (135a, 135b).

[0255] A plurality of coupling grooves (1354) may be formed on the outer wall portion (1353) or the inner wall portion (1351) of the shell body (135a, 135b). In this embodiment, a plurality of coupling grooves (1354) are formed on the outer wall portion (1353). The plurality of coupling grooves (1354) are arranged spaced apart from each other along the circumferential direction of the shell body (135a, 135b).

[0256] A coupling protrusion (1384) is provided on the shell cover (138a, 138b). The coupling protrusion (1384) may be formed to protrude radially from the outer surface of the shell cover (138a, 138b). The coupling protrusion (1384) may be arranged to face the coupling groove (1354) in the axial direction. A plurality of coupling protrusions (1384) may be coupled to a plurality of coupling grooves (1354). Through this, the shell cover (138a, 138b) and the shell body (135a, 135b) may be fastened by the coupling of the coupling protrusion (1384) and the coupling groove (1354).

[0257] A bearing mounting portion is formed on the first surface (1381) of the shell cover (138a, 138b). The bearing mounting portion may be configured by dividing the first surface (1381) of the shell cover (138a, 138b) into N equal sections, and continuously dividing the first to Nth bearing mounting portions into the divided circumferential sections.

[0258] A shaft penetration hole may be formed in the center of the shell cover (138a, 138b). The rotation shaft (118) may pass through the shaft penetration hole. The inner circumferential surface of the shell cover (138a, 138b) may not be in contact with the rotation shaft (118) and may surround the rotation shaft (118).

[0259] A plurality of injection holes (139) may be formed in the shell cover (138a, 138b). The injection holes (139) may be arranged on the inside of the bearing mounting portion. The injection holes (139) may be formed to be inclined at a preset angle with respect to the axial direction.

[0260] One side of the injection hole (139) may be connected to the cooling channel (136a, 136b). One side of the injection hole (139) may be arranged adjacent to the inner surface of the shell cover (138a, 138b). One side of the injection hole (139) may be arranged adjacent to the inner wall portion (1351).

[0261] The other side of the injection hole (139) can be connected to the gap between the top foil (131) of the thrust bearing (130a, 130b) and the first surface (1191) of the thrust runner (119). The other side of the injection hole (139) can be arranged adjacent to the radially inner end of the thrust bearing (130a, 130b).

[0262] The radial height (h2) of the other side of the injection hole (139) based on the inner surface of the shell cover (138a, 138b) is greater than the radial height (h1) of one side of the injection hole (139). Through this, the injection hole (139) can guide the flow direction of the working fluid from the inner wall portion (1351) on the radially inner side toward the thrust bearing (130a, 130b) on the radially outer side.

[0263] The injection holes (139) can be formed one by one in each circumferential section of the shell cover (138a, 138b). The injection holes (139) can be arranged to correspond to the number of bearing seating portions partitioned in the circumferential direction of the shell cover (138a, 138b). The injection holes (139) can be arranged at the center of the circumferential direction of the bearing seating portion or can be arranged on one side in the circumferential direction from the center of the bearing seating portion.

[0264] In this embodiment, the injection hole (139) is shown as being arranged on one side in the circumferential direction from the center of the circumferential direction of the bearing mounting portion. The injection hole (139) can be arranged close to the fixed portion (1311), which is the starting point of the top foil (131).

[0265] Through this, the working fluid injected through the injection hole (139) can form a rotational flow in the rotational direction of the thrust runner (119). The working fluid can rotate from the fixed part (1311), which is the starting point of the top foil (131), to the free end (1314), which is the end point of the top foil (131), along the circumferential direction of the thrust runner (119).

[0266] Referring to Fig. 7, a fixing groove (140) may be formed in the shell cover (138a, 138b). The fixing groove (140) may be formed to be recessed from the first surface (1381) of the shell cover (138a, 138b) toward the second surface of the shell cover (138a, 138b). The fixing groove (140) may extend radially through the shell cover (138a, 138b).

[0267] The fixed groove (140) may have a hook-shaped cross-sectional shape. The cross-sectional shape of the fixed groove (140) may include a straight groove (141) and a curved groove (142). The straight groove (141) may be formed to be axially recessed from the first surface (1381) of the shell cover (138a, 138b) toward the second surface of the shell cover (138a, 138b). The curved groove (142) may be formed in an arc or semicircle shape along the circumferential direction of the shell cover (138a, 138b).

[0268] The width of the fixed groove (140) can be formed to correspond to the thickness of the top foil (131). The fixed portion (1311) of the top foil (131) can be inserted into the fixed groove (140) and bent to be fixed to the shell cover (138a, 138b).

[0269] Through this, the top foil (131) can be fixed to the bearing shell (134a, 134b) by a simple joint structure without a fixing means such as adhesive or welding.

[0270] The refrigerant used as the operating fluid of the bearing may be supplied from outside the compressor. For example, the refrigerant may be supplied from a condenser. High-pressure refrigerant discharged from the condenser may be supplied to the interior of the housing (100) of the turbocompressor.

[0271] A first connecting portion (101a) may be provided at one end of the housing (100). The thickness of the housing (100) is formed between the outer and inner surfaces of the housing (100). The first connecting portion (101a) may be formed to be radially recessed in the inner surface of the housing (100).

[0272] The first connecting portion (101a) may extend along the circumference of the housing (100). The first sealing portion (108a) and the outer surface of the first bearing housing (110a) may be connected to the first connecting portion (101a).

[0273] Through this, the first joint portion (101a) can limit the first sealing portion (108a) and the first bearing housing (110a) from moving in the radial direction.

[0274] The inner circumferential diameter of the first connecting portion (101a) is larger than the inner circumferential diameter of the housing (100). Through this, the first connecting portion (101a) can limit the axial movement of the first sealing portion (108a) and the first bearing housing (110a) due to the diameter difference (step) with the inner circumferential diameter of the housing (100).

[0275] The first impeller casing (102a) is coupled to axially cover one end of the housing (100) and the first sealing portion (108a). The first sealing portion (108a) and the first bearing housing (110a) are arranged between the first impeller casing (102a) and the housing (100). Through this, the first impeller casing (102a) can restrict the first sealing portion (108a) and the first bearing housing (110a) from moving in the axial direction.

[0276] A second coupling portion (101b) may be provided at the other end of the housing (100). The second coupling portion (101b) may be formed to be radially recessed in the inner circumference of the housing (100). The second coupling portion (101b) may extend along the circumference of the housing (100). The second sealing portion (108b) and the outer circumference of the second bearing housing (110b) may be coupled to the second coupling portion (101b).

[0277] Through this, the second joint portion (101b) can limit the second sealing portion (108b) and the second bearing housing (110b) from moving in the radial direction.

[0278] The inner circumferential diameter of the second connecting portion (101b) is larger than the inner circumferential diameter of the housing (100). Through this, the second connecting portion (101b) can limit the axial movement of the second sealing portion (108b) and the second bearing housing (110b) due to the diameter difference (step) with the inner circumferential diameter of the housing (100).

[0279] The second impeller casing (102b) is coupled to cover the other end of the housing (100) and the second sealing portion (108b) in the axial direction. The second sealing portion (108b) and the second bearing housing (110b) are arranged between the second impeller casing (102b) and the housing (100). Through this, the second impeller casing (102b) can restrict the second sealing portion (108b) and the second bearing housing (110b) from moving in the axial direction.

[0280] In order to supply external refrigerant into the interior of the housing (100), a refrigerant inlet is formed to penetrate radially on the upper side of the housing (100).

[0281] The refrigerant inlet (143a, 143b) may include a first refrigerant inlet (143a) and a second refrigerant inlet (143b).

[0282] The first refrigerant inlet (143a) may be formed to penetrate radially through one end of the housing (100). The first refrigerant inlet (143a) is configured to supply refrigerant to the first thrust bearing (130a), the second thrust bearing (130b), and the first journal bearing (129a).

[0283] The second refrigerant inlet (143b) may be formed to penetrate radially through the other end of the housing (100). The second refrigerant inlet (143b) is arranged in the opposite direction to the first refrigerant inlet (143a) with respect to the electric motor (120). The second refrigerant inlet (143b) may be arranged adjacent to the second coupling portion (101b).

[0284] The second refrigerant inlet (143b) is formed to communicate with the internal space of the housing (100). Here, the internal space of the housing (100) is arranged between the electric part (120) and the second bearing housing (110b). The second refrigerant inlet (143b) is configured to supply refrigerant to the second journal bearing (129b).

[0285] One end of the first refrigerant inlet pipe can be connected to the first refrigerant inlet port (143a). The other end of the first refrigerant inlet pipe can be connected to a condenser.

[0286] One end of the second refrigerant inlet pipe can be connected to the second refrigerant inlet port (143b). The other end of the second refrigerant inlet pipe can be connected to a condenser.

[0287] Liquid refrigerant may be included in the high-pressure refrigerant supplied from the condenser. If the liquid refrigerant is supplied directly to the fluid film formed between the thrust bearing (130a, 130b) and the thrust runner (119), there is a problem that the fluid film is impacted, thereby reducing the bearing's support performance.

[0288] To solve this problem, a plurality of liquid refrigerant prevention chambers are provided inside the first bearing housing (110a). The plurality of liquid refrigerant prevention chambers (144a, 144b) may be composed of a first liquid refrigerant prevention chamber (144a) and a second liquid refrigerant prevention chamber (144b).

[0289] The first liquid refrigerant prevention chamber (144a) and the second liquid refrigerant prevention chamber (144b) may be positioned radially opposite to each other with respect to the second bearing mounting portion (111b). For example, the first liquid refrigerant prevention chamber (144a) may be positioned above the second bearing mounting portion (111b). The second liquid refrigerant prevention chamber (144b) may be positioned below the second bearing mounting portion (111b).

[0290] The liquid refrigerant prevention chamber (144a, 144b) is arranged radially outside the second bearing mounting portion (111b). The liquid refrigerant prevention chamber (144a, 144b) may have a rectangular cross-sectional shape when cut along an imaginary center line that passes radially through the center of the second bearing mounting portion (111b).

[0291] The liquid refrigerant prevention chamber (144a, 144b) may be formed to be radially recessed from the first surface of the radially extended portion (114a, 114b) of the second bearing housing (110b) toward the second surface of the radially extended portion (114a, 114b). The liquid refrigerant prevention chamber (144a, 144b) may be formed to be axially open toward the first impeller casing (102a). The opening of the liquid refrigerant prevention chamber (144a, 144b) is formed to be covered by the second surface of the first impeller casing (102a).

[0292] The first liquid coolant prevention chamber (144a) is arranged upstream of the thrust bearing (130a, 130b) based on the flow direction of the operating fluid of the bearing. Based on the drawing, the first liquid coolant prevention chamber (144a) is arranged on the upper part of the first bearing housing (110a). The first liquid coolant prevention chamber (144a) is positioned higher than the thrust bearing (130a, 130b).

[0293] The second liquid refrigerant prevention chamber (144b) is arranged downstream of the thrust bearings (130a, 130b). Based on the drawing, the second liquid refrigerant prevention chamber (144b) is arranged at the lower portion of the first bearing housing (110a). The second liquid refrigerant prevention chamber (144b) is positioned lower than the thrust bearings (130a, 130b).

[0294] An inflow passage (145a) is provided inside the first bearing housing (110a). The inflow passage (145a) is arranged between the first refrigerant inlet (143a) and the first liquid refrigerant prevention chamber (144a). The inflow passage (145a) may extend in the radial direction of the first bearing housing (110a). One end of the inflow passage (145a) is connected to communicate with the first refrigerant inlet (143a). The other end of the inflow passage (145a) is connected to communicate with the first liquid refrigerant prevention chamber (144a). The diameter of the inflow passage (145a) is formed to correspond to the diameter of the first refrigerant inlet (143a).

[0295] The axial width of the liquid refrigerant prevention chamber (144a, 144b) is larger than the diameter of the first refrigerant inlet (143a). The radial height of the liquid refrigerant prevention chamber (144a, 144b) may be larger than or equal to the axial width of the liquid refrigerant prevention chamber (144a, 144b). The volume of the liquid refrigerant prevention chamber (144a, 144b) is relatively much larger than the volume of the first refrigerant inlet (143a).

[0296] Through this, the liquid refrigerant prevention chamber (144a, 144b) can change the liquid refrigerant among the high-pressure refrigerant introduced through the first refrigerant inlet (143a) and the inlet path (145a) into a gaseous refrigerant by expanding its volume.

[0297] Accordingly, the liquid refrigerant vaporizes, preventing it from impacting the fluid film. Furthermore, as the liquid refrigerant vaporizes, its temperature decreases, further improving cooling performance.

[0298] A plurality of inflow branch passages (146a, 146b) may be arranged between the first liquid refrigerant prevention chamber (144a) and the bearing shell (134a, 134b) of the thrust bearing (130a, 130b). The plurality of inflow branch passages (146a, 146b) may include a first inflow branch passage (146a) and a second inflow branch passage (146b).

[0299] The first inflow branch channel (146a) is provided on the inside of the first sealing portion (108a). One side of the first inflow branch channel (146a) is connected to one side of the first liquid refrigerant prevention chamber (144a). Here, one side of the first liquid refrigerant prevention chamber (144a) may mean, for example, one side of the lower portion of the first liquid refrigerant prevention chamber (144a).

[0300] The other side of the first inflow branch channel (146a) may be connected in communication with the cooling channel (136a, 136b) of the bearing shell (134a) of the first thrust bearing (130a). Here, the bearing shell (134a) of the first thrust bearing (130a) may be referred to as the first bearing shell (134a). The cooling channel (136a, 136b) of the first thrust bearing (130a) may be referred to as the first cooling channel (136a).

[0301] One side of the first inflow branch channel (146a) can extend axially. The other side of the first inflow branch channel (146a) can extend radially. The axial and radial channels of the first inflow branch channel (146a) are connected to each other.

[0302] The second inflow branch passage (146b) is provided inside the radial extension (114a, 114b) of the first bearing housing (110a). One side of the second inflow branch passage (146b) is connected to the other side of the first liquid refrigerant prevention chamber (144a). Here, the other side of the first liquid refrigerant prevention chamber (144a) may mean, for example, the lower other side of the first liquid refrigerant prevention chamber (144a).

[0303] One side and the other side of the first liquid refrigerant prevention chamber (144a) can be arranged axially facing opposite directions.

[0304] The other side of the second inflow branch channel (146b) may be connected in communication with the cooling channel (136a, 136b) of the bearing shell (134b) of the second thrust bearing (130b). Here, the bearing shell (134b) of the second thrust bearing (130b) may be referred to as the second bearing shell (134b). The second cooling channel (136b) of the second thrust bearing (130b) may be referred to as the second cooling channel (136b).

[0305] One side of the second inflow branch channel (146b) can extend axially. The other side of the second inflow branch channel (146b) can extend radially. The axial and radial channels of the second inflow branch channel (146b) are connected to each other.

[0306] The first inflow branch channel (146a) and the second inflow branch channel (146b) can be arranged in opposite directions with respect to the first liquid refrigerant prevention chamber (144a).

[0307] The lower part of the radial flow path of the first inflow branch channel (146a) can be connected in communication with the flow path inlet (137a) of the first bearing shell (134a). The lower part of the radial flow path of the second inflow branch channel (146b) can be connected in communication with the flow path inlet (137a) of the second bearing shell (134b).

[0308] A plurality of outlet branch passages (147a, 147b) may be arranged between the second liquid refrigerant prevention chamber (144b) and the bearing shells (134a, 134b) of the thrust bearings (130a, 130b). The plurality of outlet branch passages (147a, 147b) may include a first outlet branch passage (147a) and a second outlet branch passage (147b).

[0309] The first outflow branch channel (147a) is provided on the inside of the first sealing portion (108a). One side (upper side in the drawing) of the first outflow branch channel (147a) can be connected in communication with the first cooling channel (136a) of the first bearing shell (134a).

[0310] The other side (lower side in the drawing) of the first outlet branch channel (147a) is connected to one side of the second liquid refrigerant prevention chamber (144b). Here, one side of the second liquid refrigerant prevention chamber (144b) may mean, for example, one side of the upper side of the second liquid refrigerant prevention chamber (144b).

[0311] One side of the first outflow branch channel (147a) can extend radially. The other side of the first outflow branch channel (147a) can extend axially. The radial and axial channels of the first outflow branch channel (147a) are connected to each other in communication.

[0312] The second outflow branch channel (147b) is provided inside the radial extension (114a, 114b) of the first bearing housing (110a). One side of the second outflow branch channel (147b) can be connected to the second cooling channel (136b) of the second bearing shell (134b).

[0313] The upper part of the radial flow path, which is one side of the second outflow branch flow path (147b), can be connected to the flow path outlet (137b) of the second bearing shell (134b).

[0314] The other side of the second outlet branch channel (147b) is connected to the other side of the second liquid refrigerant prevention chamber (144b). Here, the other side of the second liquid refrigerant prevention chamber (144b) may mean, for example, the upper other side of the second liquid refrigerant prevention chamber (144b).

[0315] One side and the other side of the second liquid refrigerant prevention chamber (144b) can be arranged axially facing opposite directions.

[0316] One side of the second outflow branch channel (147b) can extend radially. The other side of the second outflow branch channel (147b) can extend axially. The radial and axial channels of the second outflow branch channel (147b) are connected to each other.

[0317] The first outflow branch channel (147a) and the second outflow branch channel (147b) can be arranged in opposite directions with respect to the second liquid refrigerant prevention chamber (144b).

[0318] An outflow channel (145b) is provided at the lower portion of the first bearing housing (110a). The outflow channel (145b) may be positioned lower than the first outflow branch channel (147a) and the second outflow branch channel (147b).

[0319] The outflow path (145b) may extend in the axial direction of the first bearing housing (110a). One side of the outflow path (145b) may be formed to be in communication with the lower side of the second liquid refrigerant prevention chamber (144b). The other side of the outflow path (145b) may be connected to be in communication with the internal space between the radially extended portion (114a, 114b) of the first bearing housing (110a) and the electric motor (120).

[0320] A Euro communication hole (not shown) may be provided in the second bearing shell (134b). The Euro communication hole may be formed to penetrate the radially inner end of the shell body (135a, 135b) of the second bearing shell (134b) in the axial direction or at an angle set with respect to the axial direction.

[0321] One side of the euro communication hole can be connected to the second cooling channel (136b) of the second bearing shell (134b). The other side of the euro communication hole can be connected to the gap between one end of the first journal bearing (129a) and the rotation shaft (118).

[0322] Through this, the refrigerant can be supplied to the first journal bearing (129a) through the refrigerant communication hole from the second cooling channel (136b) of the second bearing shell (134b). The refrigerant supplied to the first journal bearing (129a) forms a fluid film in the gap. The first journal bearing (129a) can support the radial load of the rotating shaft (118) by the dynamic pressure formed in the fluid film.

[0323] The refrigerant introduced through the second refrigerant inlet (143b) can be supplied to the second journal bearing (129b).

[0324] For this purpose, a cooling passage (112) may be provided inside the second bearing housing (110b).

[0325] The cooling channel (112) may be formed to be recessed from the first surface of the radial extension (114a, 114b) of the second bearing housing (110b) toward the second surface of the radial extension (114a, 114b) of the second bearing housing (110b). Here, the radial extension (114a, 114b) of the second bearing housing (110b) may be referred to as a second radial extension (114a, 114b). The axial extension (113a, 113b) of the second bearing housing (110b) may be referred to as a second axial extension (113a, 113b).

[0326] Here, the first surface of the second radial extension portion (114a, 114b) may be arranged toward the second sealing portion (108b). The second surface of the second radial extension portion (114a, 114b) may be arranged toward the power unit (120). The thickness of the second radial extension portion (114a, 114b) is formed between the first surface and the second surface of the second radial extension portion (114a, 114b).

[0327] The cooling channel (112) can extend in the radial direction of the second radial extension portion (114a, 114b). The cooling channel (112) can extend along the circumferential direction of the second radial extension portion (114a, 114b).

[0328] The radially inner side of the cooling channel (112) can be connected to the gap between one side of the inner surface of the second journal bearing (129b) and the rotation shaft (118). Here, one side of the second journal bearing (129b) can mean the inner end of the second radially extended portion (114a, 114b).

[0329] The second bearing housing (110b) may further include a communication channel inlet (115a) and a communication channel outlet (115b). The communication channel inlet (115a) may be formed to penetrate the second radial extension portion (114a, 114b) in the axial direction.

[0330] One side of the communication channel inlet (115a) can be connected to the internal space between the electric part (120) and the second radial extension part (114a, 114b). The other side of the communication channel inlet (115a) can be connected to the upper side of the cooling channel (112).

[0331] The communication path outlet (115b) may be formed to penetrate in the axial direction of the second radial extension portion (114a, 114b). One side of the communication path outlet (115b) may be connected to the internal space between the electric unit (120) and the second radial extension portion (114a, 114b).

[0332] The other side of the communication channel outlet (115b) can be connected to the lower side of the cooling channel (112). The communication channel inlet (115a) and the communication channel outlet (115b) can be arranged on opposite sides in the radial direction with respect to the rotation axis (118).

[0333] A refrigerant outlet (148) may be formed to penetrate radially at the lower side of the other end of the housing (100). One side of a refrigerant outlet pipe (149) may be connected to the refrigerant outlet (148). The other side of the refrigerant outlet pipe (149) may be connected to the suction port (105a, 105b) of the second impeller casing (102b).

[0334] According to this configuration, the refrigerant introduced into the second refrigerant inlet (143b) flows into the internal space between the electric motor (120) and the second bearing housing (110b). The refrigerant flows into the cooling channel (112) of the second bearing housing (110b) through the communication channel inlet (115a).

[0335] The refrigerant can be supplied from the cooling channel (112) of the second bearing housing (110b) to the gap between one side of the inner surface of the second journal bearing (129b) and the rotary shaft (118). The refrigerant supplied to the second journal bearing (129b) forms a fluid film in the gap. The second journal bearing (129b) can support the radial load of the rotary shaft (118) by the dynamic pressure formed in the fluid film.

[0336] Additionally, the refrigerant can be supplied to the second journal bearing (129b) to cool the second journal bearing (129b).

[0337] Below, the process of supplying refrigerant to the thrust bearing (130a, 130b) and its effect will be described.

[0338] High-pressure refrigerant discharged from the refrigerant outlet of the condenser can be supplied into the interior of the housing (100) through the first refrigerant inlet pipe. The refrigerant can be introduced into the interior of the first bearing housing (110a) through the first refrigerant inlet port (143a) connected to the first refrigerant inlet pipe.

[0339] The refrigerant can be introduced into the first liquid refrigerant prevention chamber (144a) through the first refrigerant inlet (143a). If the refrigerant introduced into the first liquid refrigerant prevention chamber (144a) contains liquid refrigerant, the liquid refrigerant can expand in volume as it is introduced into the first liquid refrigerant prevention chamber (144a) which has a volume larger than that of the first refrigerant inlet (143a).

[0340] Liquid refrigerants can vaporize when their volume expands. The vaporized refrigerant cools to a temperature lower than the liquid refrigerant temperature due to the heat of vaporization.

[0341] A portion of the gaseous refrigerant, the temperature of which has been lowered, can move from the first liquid refrigerant prevention chamber (144a) to the first inflow branch passage (146a) branched into the interior of the first sealing portion (108a). The refrigerant can flow into the first cooling passage (136a) of the shell body (135a, 135b) of the first bearing shell (134a) through the first inflow branch passage (146a).

[0342] Another portion of the above-mentioned gaseous refrigerant may move from the first liquid refrigerant prevention chamber (144a) to the second inflow branch passage (146b) branched into the interior of the first bearing housing (110a). The refrigerant may flow into the second cooling passage (136b) of the second bearing shell (134b) through the second inflow branch passage (146b).

[0343] The refrigerant introduced into the first cooling channel (136a) can be sprayed into the gap between the first thrust bearing (130a) and the first surface (1191) of the thrust runner (119) through the spray hole (139) of the shell cover (138a) of the first bearing shell (134a). The refrigerant sprayed into the gap forms a fluid film.

[0344] The above fluid film can form dynamic pressure by the rotation of the thrust runner (119).

[0345] Through this, the first thrust bearing (130a) can support the axial load acting on the first surface (1191) of the thrust runner (119) by dynamic pressure.

[0346] In addition, the coolant injected into the gap can cool the heat generated due to fluid friction between the top foil (131) of the first thrust bearing (130a) and the first surface (1191) of the thrust runner (119).

[0347] The refrigerant introduced into the second cooling channel (136b) can be sprayed into the gap between the second thrust bearing (130b) and the second surface of the thrust runner (119) through the spray hole (139) of the shell cover (138b) of the second bearing shell (134b). The refrigerant sprayed into the gap forms a fluid film.

[0348] The above fluid film can form dynamic pressure by the rotation of the thrust runner (119).

[0349] Through this, the second thrust bearing (130b) can support the axial load acting on the second surface of the thrust runner (119) by dynamic pressure.

[0350] In addition, the coolant injected into the gap can cool the heat generated due to fluid friction between the top foil (131) of the second thrust bearing (130b) and the second surface of the thrust runner (119).

[0351] Therefore, according to the present invention, the thrust bearing (130a, 130b) forms a cooling channel (136a, 136b) and an injection hole (139) inside the bearing shell (134a, 134b). The bearing shell (134a, 134b) includes a shell body (135a, 135b) and a shell cover (138a, 138b). The shell cover (138a, 138b) is coupled to cover one side of the shell body (135a, 135b). The thrust bearing (130a, 130b) can be mounted on the shell cover (138a, 138b).

[0352] Cooling channels (136a, 136b) are formed inside the shell body (135a, 135b). Injection holes (139) are formed at a predetermined angle with respect to the axial direction on the radially inner side of the shell cover (138a, 138b).

[0353] The refrigerant supplied from the condenser to the interior of the compressor housing (100) is not directly sprayed onto the thrust bearing (130a, 130b), but is indirectly sprayed onto the thrust bearing (130a, 130b) through the cooling path (136a, 136b) and spray hole (139) formed inside the bearing shell (134a, 134b).

[0354] For example, the refrigerant is sprayed from the refrigerant passage through the injection hole (139) to one side of the thrust runner (119). As the high-pressure refrigerant hits one side of the thrust runner (119), the spray speed and spray pressure are reduced.

[0355] Additionally, the coolant reflected from one side of the thrust runner (119) can flow into the radial inner side of the gap between the thrust runner (119) and the top foil (131) of the thrust bearing (130a, 130b).

[0356] The refrigerant introduced radially inwardly of the above gap moves radially outwardly of the gap due to centrifugal force resulting from the rotation of the thrust runner (119) and forms a fluid film.

[0357] In addition, the fluid film formed in the gap forms a dynamic pressure by friction with one surface of the thrust runner (119) that rotates in the circumferential direction from the fixed portion (1311), which is the starting point of the top foil (131), toward the free end (1314), which is the end point of the top foil (131).

[0358] Through this, the thrust bearing (130a, 130b) can support the axial load of the thrust runner (119) by the dynamic pressure of the fluid film.

[0359] In addition, since the coolant is reflected on one surface of the thrust runner (119) and then supplied to the gap between the thrust bearing (130a, 130b) and the thrust runner (119), the shock caused by the coolant being directly supplied to the bearing can be alleviated.

[0360] Heat is generated due to friction of the fluid film in the above gap.

[0361] The refrigerant injected through the cooling hole is relatively lower than the temperature of the fluid film.

[0362] Through this, the coolant supplied through the gap can cool the heat of the thrust bearing (130a, 130b).

[0363] In addition, the refrigerant supplied into the interior of the housing (100) can move to the liquid refrigerant prevention chamber (144a, 144b) through the radial communication passage inlet (115a) and be vaporized by volume expansion. Through this, the liquid refrigerant can be prevented from flowing into the thrust bearing (130a, 130b).

[0364] Accordingly, the liquid refrigerant prevention chamber (144a, 144b) blocks the inflow of liquid refrigerant, thereby solving the problem of the inflow of liquid refrigerant causing impact and damage to the fluid film, thereby lowering the bearing's support performance.

[0365] In addition, the liquid refrigerant prevention chamber (144a, 144b) vaporizes the liquid refrigerant and absorbs the heat of the liquid refrigerant as vaporization heat, thereby lowering the temperature of the refrigerant to be supplied to the thrust bearing (130a, 130b), thereby improving the cooling performance of the thrust bearing (130a, 130b).

[0366] In addition, the first and second inlet branch channels (146a, 146b) extending radially from the communication channel inlet (115a) of the first bearing housing (110a), the liquid refrigerant prevention chamber (144a, 144b), and the cooling channels (136a, 136b) inside the shell body (135a, 135b) of the bearing shell (134a, 134b) are each extended radially, so that the channel structure is simple and the flow resistance is minimized, thereby sufficiently securing the flow rate of the refrigerant.

[0367] Moreover, the injection holes (139) formed in the shell covers (138a, 138b) of the bearing shells (134a, 134b) are formed at least once for each thrust bearing (130a, 130b) spaced at equal intervals along the circumferential direction, so that they can simultaneously supply air to a plurality of thrust bearings (130a, 130b), thereby efficiently cooling the thrust bearings (130a, 130b).

[0368] In addition, the injection hole (139) formed in the shell cover (138a, 138b) of the bare shell is formed to be inclined toward the inner end of the thrust bearing (130a, 130b), so that the refrigerant can be smoothly supplied by the centrifugal force generated by the rotation of the thrust runner (119).

[0369] 4. Description of the configuration of a separable thrust bearing (230) according to another embodiment of the present invention.

[0370] FIG. 9 is a conceptual diagram showing a view of a separable thrust bearing (230) according to another embodiment in FIG. 3 viewed in the axial direction.

[0371] Fig. 10 is a cross-sectional view taken along XX in Fig. 9, and is a conceptual diagram showing the working fluid being sprayed through a cooling hole into a thrust bearing (230).

[0372] This embodiment differs from the embodiments of FIGS. 1 to 8 described above in that the thrust bearing (230) is detachably coupled to the bearing shell (234).

[0373] The bearing shell (234) may include a fixing pin (240). The fixing pin (240) may be formed to protrude axially from the first surface (2381) of the shell cover (238) of the bearing shell (234). The fixing pin (240) may be formed integrally with the shell cover (238) or may be coupled to the shell cover (238). In the present embodiment, the fixing pin (240) is shown coupled to the shell cover (238).

[0374] A fixing groove (241) may be formed on the first surface (2381) of the shell cover (238) so that a fixing pin (240) can be coupled thereto. The fixing groove (241) may be formed to be sunken from the first surface (2381) of the shell cover (238) toward the second surface. The fixing groove (241) may be arranged on the outside of the thrust bearing (230). The shapes of the fixing groove (241) and the fixing pin (240) may be formed to correspond to each other and be matched.

[0375] A plurality of fixed grooves (241) may be provided. The plurality of fixed grooves (241) may be arranged at equal intervals in the circumferential direction along the outer periphery of the shell cover (238).

[0376] In this embodiment, four fixing grooves (241) are provided. The plurality of fixing grooves (241) are spaced at 90-degree intervals.

[0377] The fixed pin (240) may be formed in a cylindrical shape. A portion of the fixed pin (240) is received and coupled into the fixed groove (241). Through this, the fixed pin (240) can be supported on the shell cover (238) by the fixed groove (241).

[0378] Another part of the fixed pin (240) protruding from the fixed groove (241) is configured to fix the thrust bearing (230) to the first surface (2381) of the shell cover (238). The fixed pin (240) is provided in multiple pieces.

[0379] The thrust bearing (230) may include a mounting guide (2331). The mounting guide (2331) may be formed to protrude radially outward from the outer periphery of the bearing plate (233) toward the fixing pin (240).

[0380] A plurality of mounting guides (2331) are provided. The plurality of mounting guides (2331) are formed to protrude radially from the outer circumference of the bearing plate (233).

[0381] A guide groove (2332) may be formed on the inner side of the mounting guide (2331). The guide groove (2332) is formed to be recessed radially inward from the outer end of the mounting guide (2331). The guide groove (2332) may be formed to be open radially outward.

[0382] The depth of the radially inward recess of the guide groove (2332) may be greater than or equal to the diameter of the fixed pin (240). The width of the guide groove (2332) may be formed to correspond to the diameter of the fixed pin (240).

[0383] At least a portion of the fixed pin (240) can be accommodated in the guide groove (2332). The fixed pin (240) can be slidably coupled radially along the guide groove (2332).

[0384] Through this, the mounting guide (2331) is fitted into the fixed pin (240) through the guide groove (2332), so that the thrust bearing (230) can be detachably coupled to the shell cover (238).

[0385] Since other components are the same or similar to the embodiments of FIGS. 1 to 8 described above, duplicate descriptions will be omitted.

[0386] 5. Description of the configuration of a thrust bearing (330) according to another embodiment of the present invention.

[0387] Figure 11 is a conceptual diagram showing that the coolant in Figure 4 is sprayed obliquely toward the center of the thrust bearing (330) in the radial direction through the spray hole (339).

[0388] This embodiment is different from the embodiments of FIGS. 1 to 10 described above in that the injection direction of the injection hole (339) is formed to be inclined toward the center of the circumference of the thrust bearing (330) with respect to the radial direction.

[0389] A plurality of thrust bearings (330) can be spaced apart from each other in sections divided in the circumferential direction of the bearing shell (334). One injection hole (339) is formed in each section of the shell cover (338). Through this, the coolant can be injected into the thrust bearings (330) through the injection holes (339).

[0390] The refrigerant is supplied to the gap between the top foil (331) of the thrust bearing (330) and the thrust runner (119) to form a fluid film. The top foil (331) is fixed, and the thrust runner (119) rotates in the circumferential direction, thereby generating fluid friction.

[0391] Due to this, high temperature heat is generated in the thrust bearing (330). In particular, there is a problem that the temperature of the central portion of the thrust bearing (330) in the circumferential direction is further increased because it is far from the starting point where the coolant is sprayed.

[0392] Here, the circumferential central portion of the thrust bearing (330) means the middle portion when the top foil (331) of the thrust bearing (330) is divided into three parts along the circumferential direction from the fixed portion (1311) (left end in the drawing) of the top foil (331) toward the free end (1314) (right end in the drawing).

[0393] To solve this, the injection hole (339) can be formed so that the injection direction is directed toward the central portion of the circumference of the thrust bearing (330).

[0394] One end of the injection hole (339) is arranged to be radially aligned with the left end of the fixing portion (1311) of the top foil (331). The other end of the injection hole (339) is arranged at a point moved at a predetermined interval in the circumferential direction (clockwise) from an imaginary radial center line passing through the left end of the fixing portion (1311) of the top foil (331).

[0395] One end of the injection hole (339) refers to one axial end of the injection hole (339) formed through the second surface of the shell cover (338). The other end of the injection hole (339) refers to the other axial end of the injection hole (339) formed through the first surface (1381) of the shell cover (338).

[0396] In this embodiment, the injection hole (339) is formed to be inclined at a preset angle with respect to the axial direction (see FIG. 6 and FIG. 10), and may also be formed to be inclined at a preset angle with respect to the radial direction (see FIG. 11).

[0397] Through this, the injection direction of the injection hole (339) is directed toward the central portion of the circumference of the thrust bearing (330) where the heat generated from the fluid film is at the highest temperature, so that the thrust bearing (330) can be efficiently cooled. In addition, not only can the working fluid be sufficiently supplied to the thrust bearing (330), but also the cooling performance can be maximized.

[0398] Since other components are the same or similar to the embodiments of FIGS. 1 to 10 described above, duplicate descriptions will be omitted.

[0399] 6. Description of the configuration of a thrust bearing (430) according to another embodiment of the present invention.

[0400] Figure 12 is a conceptual diagram showing a plurality of injection holes (439a, 439b) formed for each thrust bearing (430) in Figure 4.

[0401] This embodiment shows a shape in which a plurality of injection holes (439a, 439b) are formed in each section of a plurality of thrust bearings (430) divided in the circumferential direction.

[0402] A plurality of thrust bearings (430) can be arranged in N equal sections spaced apart along the circumference of the shell cover (438) of the bearing shell (434). In this embodiment, the thrust bearings (430) are shown as being provided in six pieces. The top foil (431) of the thrust bearing (430) can be extended by approximately 60 degrees along the circumference.

[0403] The gap between two thrust bearings (430) adjacent to each other in the circumferential direction is very narrow. The fixed portion (4311), which is the starting point of one of the top foils (431) of the two thrust bearings (430) adjacent to each other in the circumferential direction, and the free end (4314), which is the ending point of the other top foil (431) can be arranged adjacent to each other in the circumferential direction.

[0404] The plurality of injection holes (439a, 439b) may be arranged in pairs of two for each section divided in the circumferential direction. The plurality of injection holes (439a, 439b) may be arranged on the inside of the thrust bearing (430). The plurality of injection holes (439a, 439b) may be arranged spaced apart from each other in the circumferential direction.

[0405] The plurality of injection holes (439a, 439b) may be composed of a first injection hole (439a) and a second injection hole (439b). The first injection hole (439a) may be arranged adjacent to an imaginary radial center line that passes radially through the center of the fixing part (4311) of the top foil (431) and the shell cover (438).

[0406] The second injection hole (439b) can be arranged spaced apart from the first injection hole (439a) in the circumferential direction.

[0407] The first injection hole (439a) and the second injection hole (439b) can simultaneously inject refrigerant through a single thrust bearing (430). The positions of the first injection hole (439a) and the second injection hole (439b) are different.

[0408] The location of the first injection hole (439a) is close to the fixed part (4311) of the top foil (431). The location of the second injection hole (439b) is close to the central part of the circumference of the top foil (431).

[0409] The injection directions of the first injection hole (439a) and the second injection hole (439b) may be formed differently.

[0410] For example, the spray direction of the first spray hole (439a) may be directed toward the fixed portion (4311) of the top foil (431). The spray direction of the second spray hole (439b) may be directed toward the central portion of the circumference of the top foil (431).

[0411] The first and second injection holes (439a, 439b) can cool one thrust bearing (430).

[0412] Through this, the plurality of injection holes (439a, 439b) can not only sufficiently supply the working fluid to the thrust bearing (430), but also further improve the cooling performance of the thrust bearing (430).

Claims

1. In a thrust bearing, a thrust runner is formed to protrude in the radial direction of the rotation shaft from the outer surface of the rotation shaft and is arranged with a gap therebetween, and supports the axial load of the thrust runner. Includes a bearing shell supporting the above thrust bearing, The above bearing shell, A shell body having a cooling passage through which a working fluid flows; and A thrust bearing including a shell cover that is coupled to cover one side of the shell body, has an injection hole communicating with the cooling channel, and forms a fluid film by injecting the working fluid into the gap through the injection hole.

2. In paragraph 1, The above working fluid is a refrigerant thrust bearing.

3. In paragraph 1, A top foil arranged to face the thrust runner with the above gap; and A thrust bearing comprising a plurality of bump portions formed in a curved shape and a plurality of connecting portions connecting the plurality of bump portions, and including a bump foil that elastically supports the top foil.

4. In paragraph 3, Further comprising a bearing plate mounted on one side of the above shell cover, One end of the top foil is fixed to one side of the bearing plate, and the other end of the top foil is a free end. The above bump foil is a thrust bearing arranged between the bearing plate and the top foil.

5. In paragraph 1, The above shell body is formed in a cylindrical shape, The above shell cover is formed in a circular shape having the same diameter as the above shell body, The above shell cover, a first surface arranged toward the thrust runner; and A second surface disposed toward the shell body is included, and the thickness of the shell cover is formed between the first surface and the second surface, The above injection hole is arranged radially inside the shell cover, A thrust bearing in which the injection hole penetrates the thickness of the shell cover and is formed to be inclined radially outwardly of the rotation axis with respect to the axial direction of the rotation axis.

6. In paragraph 5, A thrust bearing in which the above injection hole is formed to be inclined in the circumferential direction with respect to the radial direction of the shell cover.

7. In paragraph 5, The first surface of the above shell cover is divided into N sections of 360 degrees, and thrust bearings are arranged in each of the N sections. A thrust bearing in which the above injection holes are arranged one or more times per section.

8. In paragraph 1, The above shell body is, An inner wall portion surrounding the above rotation axis; An outer wall portion spaced radially outward from the inner wall portion; and Including a connecting wall connecting one end of the inner wall portion and the outer wall portion, A thrust bearing in which the cooling channel is formed between the inner wall portion, the outer wall portion, and the connecting wall, and extends circumferentially along the periphery of the inner wall portion.

9. In paragraph 8, The above shell cover, a first surface facing the thrust runner; and Including a second surface facing the shell body, A thrust bearing in which the injection hole penetrates the thickness of the shell cover formed between the first surface and the second surface, one side of the injection hole is adjacent to the inner wall portion, and the other side of the injection hole is disposed adjacent to the radially inner end portion of the thrust bearing.

10. In paragraph 8, The above shell body is, A flow path inlet formed radially through one side of the outer wall to allow the working fluid to flow into the cooling path; and A thrust bearing including a flow path outlet formed radially through the other side of the outer wall portion so that the working fluid flows out of the cooling path.

11. In paragraph 3, The above shell cover, a first surface facing the thrust runner; and A second surface facing the shell body is included, and the thickness of the shell cover is formed between the first surface and the second surface, A thrust bearing in which a fixing groove is formed to extend radially for fixing one end of the top foil by inserting it into the inner thickness of the shell cover.

12. In paragraph 11, A thrust bearing in which the above fixed groove is formed in a hook shape.

13. In paragraph 4, The above shell cover, a first surface facing the thrust runner; and A second surface facing the shell body is included, and the thickness of the shell cover is formed between the first surface and the second surface, A fixing pin for fixing the thrust bearing to the shell cover protrudes from the first surface toward the thrust runner, A thrust bearing further comprising a mounting guide having a guide groove that protrudes toward the fixing pin from the outer periphery of the bearing plate and into which the fixing pin is slidably engaged.

14. In paragraph 13, The above shell cover, A thrust bearing further comprising a fixing groove formed to be sunken toward the second surface on the first surface and to which the fixing pin is coupled.

15. Housing; A rotary shaft rotatably provided inside the housing; An impeller coupled to one end of the above rotating shaft; An electric motor having a rotor connected to the above-mentioned rotational axis and a stator surrounding the rotor, and driving the impeller; A thrust runner formed to protrude in the radial direction of the rotational axis from the outer surface of the rotational axis; A thrust bearing arranged with a gap between the thrust runner and the thrust runner to support the axial load of the thrust runner; and Includes a bearing shell supporting the above thrust bearing, The above bearing shell, A shell body having a cooling passage through which a working fluid flows; and A turbo compressor comprising a shell cover that is coupled to cover one side of the shell body, has an injection hole communicating with the cooling channel, and forms a fluid film by injecting the working fluid into the gap through the injection hole.

16. In paragraph 15, A turbocompressor further comprising an impeller casing that accommodates the impeller and has a diffuser therein that converts velocity energy of the working fluid sucked by the impeller into pressure energy.

17. In paragraph 15, The above impeller, A first impeller coupled to one end of the above rotating shaft; and It includes a second impeller coupled to the other end of the above rotating shaft, A first journal bearing disposed between the thrust bearing and the rotor and supporting a radial load at one end of the rotation shaft; and A turbocompressor comprising a second journal bearing disposed between the second impeller and the rotor and supporting a radial load of the other end of the rotating shaft.

18. In paragraph 15, The above thrust runner, A first surface facing the impeller; A second surface facing the electric part is included, and the thickness of the thrust runner is formed between the first surface and the second surface of the thrust runner, The above thrust bearing, A first thrust bearing arranged toward the first surface; A first bearing shell supporting the first thrust bearing; A second thrust bearing arranged toward the second surface; and A turbocompressor including a second bearing shell supporting the second thrust bearing.

19. In paragraph 18, A refrigerant inlet formed to penetrate the housing in a radial direction and to introduce refrigerant supplied from a condenser into the internal space of the housing; A first liquid refrigerant prevention chamber provided inside the housing, connected to the refrigerant inlet, and having a volume larger than the volume of the refrigerant inlet; An inlet branch passage connected to the first liquid refrigerant prevention chamber and the inlet formed on one side of the shell body, and transmitting the refrigerant to the cooling passage; A second liquid refrigerant prevention chamber provided inside the housing and positioned in the opposite direction of the first liquid refrigerant prevention chamber with respect to the rotation axis; A turbo compressor including a flow outlet formed on the other side of the shell body and a flow branch passage connected to the second liquid refrigerant prevention chamber, and which causes the refrigerant to flow from the cooling passage to the second liquid refrigerant prevention chamber.

20. In paragraph 19, A sealing portion coupled to one end of the housing and accommodating and supporting the first bearing shell; and A bearing housing is disposed between the sealing portion and the electric portion, and includes a bearing housing that accommodates and supports the second bearing shell. The above inflow stream is: A first inflow branch passage provided on one side of the inner portion of the sealing portion and connecting one side of the first liquid refrigerant prevention chamber and the passage inlet of the first bearing shell; and A second inflow branch passage is provided on one side of the inside of the bearing housing and connects the other side of the first liquid refrigerant prevention chamber and the inlet of the second bearing shell. The above mentioned outflow stream is: A first outlet branch passage provided on the inner side of the sealing portion and connecting the outlet of the first bearing shell and one side of the second liquid refrigerant prevention chamber; and A turbo compressor including a second outlet branch passage provided on the inner side of the bearing housing and connecting the outlet of the second bearing shell and the other side of the second liquid refrigerant prevention chamber.

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