Turbo Compressor and Refrigeration Device

Abstract

To cool a bearing with increase of windage loss inhibited.SOLUTION: A turbo compressor (20) includes: a casing (21); an electric motor (30) housed within the casing (21); a driving shaft (40) which is rotationally driven by the electric motor (30); radial bearings (63, 67) which rotatably support the driving shaft (40); and a refrigerant passage (R) in which a liquid refrigerant for cooling the radial bearings (63, 67) flows. The refrigerant passage (R) includes first passages (74, 84) formed along an outer peripheral surface of the radial bearings (63, 67).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a turbo compressor and a refrigeration device.

Background Art

[0002] Conventionally, turbo compressors are known. Patent Document 1 discloses a refrigeration device including a turbo compressor. The refrigeration device of Patent Document 1 includes a refrigerant supply unit (refrigerant flow path) that supplies a part of the refrigerant discharged from the condenser to the turbo compressor. The refrigerant supply unit supplies the refrigerant so as to cool the drive motor (electric motor) and the bearing member (bearing) of the turbo compressor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, a part of the liquid refrigerant discharged from the condenser is supplied to the bearing via the refrigerant flow path. The liquid refrigerant supplied to the bearing cools the bearing by passing through the rotating part of the bearing.

[0005] By the way, in Patent Document 1, since the liquid refrigerant flows into the rotating part of the bearing, the flowing-in liquid refrigerant is agitated as the rotating part rotates. When the liquid refrigerant is agitated, friction occurs between the rotating part and the liquid refrigerant, and there is a problem that the loss due to this friction (so-called windage loss) increases.

[0006] An object of the present disclosure is to cool the bearing while suppressing an increase in windage loss.

Means for Solving the Problems

[0007] The first aspect includes a casing (21), an electric motor (30) having a stator (31) and a rotor (32) and housed inside the casing (21), a drive shaft (40) rotationally driven by the electric motor (30), radial bearings (63, 67) that rotatably support the drive shaft (40), and a refrigerant flow path (R) through which a liquid refrigerant for cooling the radial bearings (63, 67) flows. The refrigerant flow path (R) is a turbo compressor including first flow paths (74, 84) formed along the outer peripheral surface of the radial bearings (63, 67).

[0008] In the first aspect, the first flow paths (74, 84) of the refrigerant flow path (R) are formed along the outer peripheral surface of the radial bearings (63, 67). Therefore, the radial bearings (63, 67) can be cooled without allowing the liquid refrigerant to flow into the inside of the radial bearings (63, 67). As a result, the radial bearings (63, 67) can be cooled while suppressing an increase in windage loss caused by agitation of the liquid refrigerant.

[0009] The second aspect further includes holding parts (62, 66) that hold the radial bearings (63, 67) in the first aspect, and the first flow paths (74, 84) are formed between the inner surface of the holding parts (62, 66) and the outer peripheral surface of the radial bearings (63, 67).

[0010] In the second aspect, since the first flow paths (74, 84) are formed between the inner surface of the holding parts (62, 66) and the outer peripheral surface of the radial bearings (63, 67), the first flow paths (74, 84) can be easily formed.

[0011] The third aspect is that in the first or second aspect, the first flow paths (74, 84) are formed in a spiral shape extending in the axial direction of the drive shaft (40).

[0012] In the third aspect, since the first flow paths (74, 84) are formed in a spiral shape, the entire outer peripheral surface of the radial bearings (63, 67) can be efficiently cooled.

[0013] The fourth aspect is that in any one of the first to third aspects, it further includes a storage part (27) for storing the liquid refrigerant flowing out from the refrigerant flow path (R), the drive shaft (40) extends along the horizontal direction, and the storage part (27) is provided below the electric motor (30).

[0014] In the fourth aspect, since the storage part (27) is provided below the electric motor (30), the heat of the electric motor (30) is transferred to the liquid refrigerant accumulated in the storage part (27), and the liquid refrigerant vaporizes. Further, since the gaseous refrigerant vaporized in the storage part (27) flows around the electric motor (30), the heat of the electric motor (30) is transferred to the gaseous refrigerant, and the temperature of the gaseous refrigerant rises. Thus, the electric motor (30) can be cooled by the state change and temperature change of the refrigerant.

[0015] The fifth aspect is that in the fourth aspect, the refrigerant flow path (R) is formed above the storage part (27) and includes an outlet (76, 86) through which the liquid refrigerant flows out, and the electric motor (30) is arranged between the storage part (27) and the outlet (76, 86).

[0016] In the fifth aspect, the liquid refrigerant flowing out from the outlet (76, 86) falls by its own weight, passes through the electric motor (30), and flows down into the storage part (27). As a result, the electric motor (30) can be cooled.

[0017] The sixth aspect is that in the fifth aspect, the outlet (76, 86) opens downward.

[0018] In the sixth aspect, since the outlet (76, 86) opens downward, the liquid refrigerant easily flows downward by its own weight.

[0019] The seventh aspect is that in the fifth or sixth aspect, the stator (31) has a core (33) and a coil (34) wound around the core (33), and the coil (34) is arranged between the storage part (27) and the outlet (76, 86).

[0020] In the seventh aspect, the liquid refrigerant flowing out from the outlets (76, 86) drops onto the coil (34) due to its own weight. As the liquid refrigerant passes through the coil (34), the liquid refrigerant takes away the heat of the coil (34). As a result, the coil (34) that is prone to heat generation can be cooled.

[0021] The eighth aspect is that in any one of the first to seventh aspects, the radial bearings (63, 67) are arranged on one side and the other side of the motor (30), and the refrigerant flow path (R) includes a first refrigerant flow path (70) that cools the radial bearing (63, 67) on one side and a second refrigerant flow path (80) that cools the radial bearing (63, 67) on the other side.

[0022] In the eighth aspect, the radial bearing (63, 67) on one side can be cooled by the first refrigerant flow path (70), and the radial bearing (63, 67) on the other side can be cooled by the second refrigerant flow path (80).

[0023] The ninth aspect is that in any one of the first to eighth aspects, the refrigerant flow path (R) includes an outlet (92) for discharging the gas refrigerant formed by vaporization of the liquid refrigerant, and the outlet (92) is formed only on one side of the motor (30) in the casing (21).

[0024] In the ninth aspect, the outlet (92) from which the gas refrigerant is discharged is formed only on one side of the motor (30) in the casing (21). Therefore, the gas refrigerant flows from the other side to the one side of the motor (30) through the gap (35) formed between the stator (31) and the rotor (32) of the motor (30). As a result, the motor (30) can be cooled.

[0025] The tenth aspect is that in any one of the first to ninth aspects, it further includes a thrust bearing (69a) that rotatably supports the drive shaft (40), and the refrigerant flow path (R) includes a second flow path (73) formed along the thrust bearing (69a).

[0026] In the tenth aspect, the liquid refrigerant flowing through the second flow path (73) of the refrigerant flow path (R) can cool the thrust bearing (69a).

[0027] The eleventh aspect is a refrigeration device including the turbo compressor (20) according to any one of the first to tenth aspects.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0029] 《Embodiment》 Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of the present disclosure. Since each drawing is for conceptually explaining the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for easy understanding.

[0030] (1) Outline of the Refrigeration Device As shown in FIG. 1, the turbo compressor of the present disclosure (hereinafter also referred to as compressor (20)) is provided in a refrigeration device (1). The refrigeration device (1) has a refrigerant circuit (10) filled with a refrigerant. The refrigerant circuit (10) is composed of a main circuit (11), a sub-circuit (12), a branch circuit (13), and a return circuit (14). The main circuit (11) has a main pipe (11a), a compressor (20), a radiator (condenser) (2), a first decompression mechanism (3), and an evaporator (4). The compressor (20), the radiator (2), the first decompression mechanism (3), and the evaporator (4) are connected in series by the main pipe (11a). The first decompression mechanism (3) is an expansion valve. The main circuit (11) performs a vapor compression refrigeration cycle.

[0031] In the refrigeration cycle, the refrigerant compressed by the compressor (20) dissipates heat to the air in the radiator (2). The heat-dissipated refrigerant is decompressed by the first decompression mechanism (3) and evaporates in the evaporator (4). The evaporated refrigerant is sucked into the compressor (20).

[0032] The compressor (20) in this example is of a two-stage type. The compressor (20) has a first compression chamber (53) and a second compression chamber (58). The first compression chamber (53) is a high-pressure-side compression chamber. The second compression chamber (58) is a low-pressure-side compression chamber. In the compressor (20), the refrigerant is compressed in two stages in the first compression chamber (53) and the second compression chamber (58). The detailed configuration of the compressor (20) will be described later.

[0033] The sub-circuit (12) has a sub-pipe (12a). One end of the sub-pipe (12a) is connected to the first compression chamber (53), and the other end is connected to the second compression chamber (58). The sub-pipe (12a) connects the discharge side of the second compression chamber (58) and the suction side of the first compression chamber (53).

[0034] The branch circuit (13) has a main branch pipe (13a), a first branch pipe (13b), a second branch pipe (13c), and a second pressure reducing mechanism (5). One end of the main branch pipe (13a) is connected between the radiator (2) and the first pressure reducing mechanism (3) in the main pipe (11a). The second pressure reducing mechanism (5) is arranged in the main branch pipe (13a). The second pressure reducing mechanism (5) is an expansion valve.

[0035] The other end of the main branch pipe (13a) is connected to one end of the first branch pipe (13b) and one end of the second branch pipe (13c). In other words, the branch circuit (13) branches into two in the middle. The other ends of the first branch pipe (13b) and the second branch pipe (13c) are respectively connected to the inlets (71, 81) of the refrigerant flow path (R) of the compressor (20) described later.

[0036] The return circuit (14) has a return pipe (14a). One end of the return pipe (14a) is connected between the evaporator (4) and the compressor (20) in the main pipe (11a). The other end of the return pipe (14a) is connected to the outlet (92) of the refrigerant flow path (R) of the compressor (20) described later.

[0037] The refrigeration device (1) is an air conditioner. The air conditioner may be a cooling-only machine, a heating-only machine, or an air conditioner that switches between cooling and heating. In this case, the air conditioner has a switching mechanism (for example, a four-way switching valve) for switching the circulation direction of the refrigerant. The refrigeration device (1) may be a water heater, a chiller unit, a cooling device for cooling the air in the room, etc. The cooling device cools the air inside a refrigerator, a freezer, a container, etc. The pressure reducing mechanism is composed of an electronic expansion valve, a thermostatic expansion valve, an expander, or a capillary tube.

[0038] (2) Compressor Referring to FIG. 2, the schematic configuration of the compressor (20) will be described. The compressor (20) in this example is a two-stage type having two compression mechanisms (50). The compressor (20) includes a casing (21), an electric motor (30), a drive shaft (40), and a compression mechanism (50). The casing (21) houses the electric motor (30), the drive shaft (40), and the compression mechanism (50). The compressor (20) includes a bearing member that supports the drive shaft (40). The bearing member has a first radial bearing member (61), a second radial bearing member (65), and a thrust bearing member (69). Each bearing member includes a bearing. The compressor (20) includes a refrigerant flow path (R) through which a liquid refrigerant for cooling the bearing flows.

[0039] In the following description, the "axial direction" refers to the direction in which the drive shaft (40) extends, the "radial direction" refers to the direction orthogonal to the axial direction, and the "circumferential direction" refers to the direction along the circumference of the drive shaft (40).

[0040] (2-1) Casing The casing (21) has a body portion (22), a first closing portion (23), and a second closing portion (24). The body portion (22) is formed in a cylindrical shape with both ends in the axial direction open. The body portion (22) is arranged such that its axis extends along the horizontal direction. The first closing portion (23) closes the opening portion on one end side in the axial direction of the body portion (22). The first closing portion (23) includes a first housing (25) located at its center. The second closing portion (24) closes the opening portion on the other end side in the axial direction of the body portion (22). The second closing portion (24) includes a second housing (26) located at its center.

[0041] The body portion (22) includes a protruding portion (22b) that protrudes radially inward from the main body portion (22a) of the body portion (22). The protruding portion (22b) is provided at the axial center portion of the body portion (22). The protruding portion (22b) is formed over the entire circumference of the inner surface of the body portion (22).

[0042] A storage part (27) is formed at the bottom of the casing (21). The liquid refrigerant flowing out from the refrigerant flow path (R) is stored in the storage part (27). The storage part (27) is formed on one side and the other side of the protruding part (22b) in the lower part of the body part (22). The storage part (27) is provided in a space surrounded by the body part (22) and the radial bearing members (61, 65). Details of the refrigerant flow path (R) will be described later.

[0043] (2-2) Electric motor The electric motor (30) is arranged at the center of the body part (22). The electric motor (30) is arranged on the radially inner side of the protruding part (22b) in the body part (22). The electric motor (30) divides the internal space of the casing (21) into a first space (S1) and a second space (S2). The first space (S1) is formed on the side of the first closing part (23) (one axial side of the electric motor (30)). The second space (S2) is formed on the side of the second closing part (24) (the other axial side of the electric motor (30)).

[0044] The electric motor (30) has a stator (31) and a rotor (32). The stator (31) is formed in a cylindrical shape. The stator (31) has a core (33) and a coil (34). The core (33) is a cylindrical member made of a magnetic material. The coil (34) is wound around the core (33). The core (33) of the stator (31) is fixed to the inner peripheral surface of the protruding part (22b) in the body part (22). The coil (34) is located above the storage part (27). In other words, the storage part (27) is provided below the electric motor (30).

[0045] The rotor (32) is provided on the radially inner side of the stator (31). The rotor (32) is arranged with a gap (35) interposed between it and the core (33) of the stator (31). The rotor (32) is a cylindrical member made of a magnetic material. The gap (35) is a so-called air gap. The gap (35) communicates the first space (S1) and the second space (S2).

[0046] The motor (30) has its operating frequency (rotational speed) adjusted by an inverter device. In other words, the compressor (20) is of an inverter type with a variable rotational speed. Therefore, the rotational speed of the motor (30) varies between a relatively low rotational speed and a relatively high rotational speed.

[0047] (2-3) Drive shaft The drive shaft (40) is fixed to the axis of the rotor (32). The drive shaft (40) is rotationally driven by the motor (30). The motor (30) is disposed at a substantially central portion of the drive shaft (40). The drive shaft (40) extends along the horizontal direction. The drive shaft (40) extends along the axis of the casing (21). The drive shaft (40) has a first end portion (41) and a second end portion (42). The first end portion (41) is the end portion on the side of the first closing portion (23), and the second end portion (42) is the end portion on the side of the second closing portion (24).

[0048] In the drive shaft (40) of this example, a thrust plate (43) is provided. The thrust plate (43) is configured as a separate component from the main body (40a) of the drive shaft (40). Note that it may be configured integrally with the main body (40a) of the drive shaft (40). The thrust plate (43) of this example is provided near the first end portion (41). The thrust plate (43) is formed in a disc shape extending radially outward from the main body (40a) of the drive shaft (40).

[0049] (2-4) Radial bearing member The compressor (20) of this example has two radial bearing members (61, 65). The number and positions of the radial bearing members (61, 65) are merely an example.

[0050] The first radial bearing member (61) is disposed closer to the first end portion (41) of the drive shaft (40). The first radial bearing member (61) is disposed in the first space (S1). The first radial bearing member (61) is fixed to the body portion (22) of the casing (21). The first radial bearing member (61) has a first holding portion (62) and a first radial bearing (63).

[0051] The first holding part (62) holds the first radial bearing (63). As shown in FIG. 3, the first holding part (62) includes a first disk part (62a) and a first cylindrical part (62b). The first disk part (62a) is located at one end of the first holding part (62) in the axial direction. The first disk part (62a) is formed in an axially thick annular shape. The outer peripheral surface of the first disk part (62a) is fixed to the inner peripheral surface of the body part (22). A concave part (62c) is formed on one end surface of the first disk part (62a) in the axial direction. The concave part (62c) is recessed toward the other side in the axial direction. The internal space of the concave part (62c) is formed in a columnar shape. A thrust bearing member (69) is disposed in the concave part (62c).

[0052] The first cylindrical part (62b) is located at the other end of the first holding part (62) in the axial direction. The first cylindrical part (62b) is formed in a cylindrical shape extending in the axial direction. The coil (34) of the electric motor (30) is disposed outside the first cylindrical part (62b). In other words, the coil (34) of the electric motor (30) surrounds the outer periphery of the first cylindrical part (62b). The first cylindrical part (62b) overlaps with the coil (34) when viewed in the radial direction. The outer diameter of the first cylindrical part (62b) is smaller than the outer shape of the first disk part (62a). The outer peripheral surface of one end side of the first cylindrical part (62b) in the axial direction and the outer peripheral surface of the other end side of the first disk part (62a) in the axial direction are smoothly connected.

[0053] The first radial bearing (63) is a gas bearing that forms a gas film with the drive shaft (40) to support the load (radial load) acting on the drive shaft (40) in the radial direction. The first radial bearing (63) is disposed at the axial center of the first radial bearing member (61). The first radial bearing (63) is fixed to the inner peripheral surface of the first holding part (62). The first radial bearing (63) is formed in a cylindrical shape. The first radial bearing (63) rotatably supports the portion of the drive shaft (40) on the side of the first end (41).

[0054] The second radial bearing member (65) is arranged near the second end portion (42) of the drive shaft (40). The second radial bearing member (65) is arranged in the second space (S2). The second radial bearing member (65) is fixed to the body portion (22) of the casing (21). The second radial bearing member (65) has a second holding portion (66) and a second radial bearing (67).

[0055] The second holding portion (66) holds the second radial bearing (67). The second holding portion (66) includes a second disc portion (66a) and a second cylindrical portion (66b). The second disc portion (66a) is located at the end on the other end side in the axial direction of the second holding portion (66). The second disc portion (66a) is formed in an axially thick annular shape. The outer peripheral surface of the second disc portion (66a) is fixed to the inner peripheral surface of the body portion (22).

[0056] The second cylindrical portion (66b) is located at the end on one end side in the axial direction of the second holding portion (66). The second cylindrical portion (66b) is formed in a cylindrical shape extending in the axial direction. Outside the second cylindrical portion (66b), the coil (34) of the electric motor (30) is arranged. In other words, the coil (34) of the electric motor (30) surrounds the outer periphery of the second cylindrical portion (66b). The first cylindrical portion (62b) overlaps the coil (34) when viewed in the radial direction. The outer diameter of the second cylindrical portion (66b) is smaller than the outer shape of the second disc portion (66a). The outer peripheral surface on the other end side in the axial direction of the second cylindrical portion (66b) and the outer peripheral surface on the one end side in the axial direction of the second disc portion (66a) are smoothly connected.

[0057] The second radial bearing (67) is a gas bearing that supports the load (radial load) acting in the radial direction of the drive shaft (40) by forming a gas film between the second radial bearing (67) and the drive shaft (40). The second radial bearing (67) is arranged at the axial center portion of the second radial bearing member (65). The second radial bearing (67) is fixed to the inner peripheral surface of the second holding portion (66). The second radial bearing (67) is formed in a cylindrical shape. The second radial bearing (67) rotatably supports the portion on the second end portion (42) side of the drive shaft (40).

[0058] (2-5) Thrust bearing member The thrust bearing member (69) is fixed to the recess (62c) of the first radial bearing member (61). The thrust bearing member (69) is located near the first end portion (41) of the drive shaft (40). The thrust bearing member (69) is disposed on one side of the electric motor (30). Inside the thrust bearing member (69), a thrust bearing (69a) that slidably contacts the thrust plate (43) is formed. The thrust bearing (69a) is a gas bearing that supports the load (thrust load) acting in the axial direction of the drive shaft (40) by forming a gas film between the thrust bearing (69a) and the thrust plate (43). The thrust bearing (69a) rotatably supports the drive shaft (40).

[0059] (2-6) Compression mechanism The compression mechanism (50) of this example is a centrifugal compression mechanism that gives kinetic energy to the fluid by the centrifugal force of the impellers (52, 57) and converts this kinetic energy into pressure. The compressor (20) of this example has two compression mechanisms (50). The first compression mechanism (51) is provided on the first end portion (41) side of the drive shaft (40). The second compression mechanism (56) is provided on the second end portion (42) side of the drive shaft (40). The first compression mechanism (51) includes a first housing (25) and a first impeller (52). The first impeller (52) is connected to the first end portion (41) of the drive shaft (40). The second compression mechanism (56) includes a second housing (26) and a second impeller (57). The second impeller (57) is connected to the second end portion (42) of the drive shaft (40). Each impeller (52, 57) has a plurality of blades.

[0060] In the first compression mechanism (51), a first compression chamber (53) is formed between the first housing (25) and the first impeller (52). A first suction passage (54) for sending fluid (refrigerant) to the first compression chamber (53) is formed in the first housing (25). The first compression chamber (53) is a compression chamber on the high-pressure side. In the second compression mechanism (56), a second compression chamber (58) is formed between the second housing (26) and the impellers (52, 57). A second suction passage (59) for sending fluid (refrigerant) to the second compression chamber (58) is formed in the second housing (26). The second compression chamber (58) is a compression chamber on the low-pressure side.

[0061] (3) Compressor operation The operation of the compressor (20) will be described. When the compressor (20) is operating, the electric motor (30) is energized. As a result, the drive shaft (40) rotates. When the drive shaft (40) rotates, each impeller (52, 57) connected to the drive shaft (40) rotates.

[0062] When the second impeller (57) rotates, the refrigerant flows from the second suction passage (59) into the second compression chamber (58). In the second compression chamber (58), the refrigerant is sent radially outward by a plurality of blades, and the flow rate of the refrigerant increases. By accelerating the speed of this refrigerant, the pressure of the refrigerant increases. The refrigerant flowing into the second compression chamber (58) is compressed to an intermediate pressure. The refrigerant compressed to the intermediate pressure flows into the first suction passage (54) via the sub-circuit (12).

[0063] The refrigerant flowing into the first suction passage (54) is sent to the first compression chamber (53) by the rotation of the first impeller (52). In the first compression chamber (53), as in the second compression chamber (58), the pressure of the refrigerant increases by accelerating the speed of the refrigerant by a plurality of blades. The refrigerant flowing into the first compression chamber (53) is compressed to a high pressure. The refrigerant compressed in this way is sent to the outside of the casing (21) through a discharge passage (not shown). The refrigerant discharged from the compressor (20) is used in the refrigeration cycle of the refrigeration device (1).

[0064] (4) Refrigerant flow path Next, the refrigerant flow path (R) will be described with reference to FIGS. 2, 3, and 4.

[0065] The refrigerant flow path (R) cools the radial bearings (63, 67), the thrust bearing (69a), and the electric motor (30). Refrigerant flows through the refrigerant flow path (R). As shown in FIG. 2, the refrigerant flow path (R) includes a first refrigerant flow path (70), a second refrigerant flow path (80), and a third refrigerant flow path (90).

[0066] (4-1) First refrigerant flow path As shown in FIG. 3, the first refrigerant flow path (70) is formed in the body portion (22) of the casing (21) and the first radial bearing member (61). The first refrigerant flow path (70) cools the thrust bearing (69a) and the first radial bearing (63). The first refrigerant flow path (70) allows the liquid refrigerant to flow. The first refrigerant flow path (70) includes a first inlet (71), a first introduction path (72), a thrust bearing cooling path (73), a first radial bearing cooling path (74), a first outflow path (75), and a first outlet (76). The first radial bearing cooling path (74) corresponds to the first flow path of the present disclosure. The thrust bearing cooling path (73) corresponds to the second flow path of the present disclosure.

[0067] The first inlet (71) is an opening for allowing the liquid refrigerant to flow into the first refrigerant flow path (70). The first inlet (71) is formed at the top of the body portion (22). The first inlet (71) is formed near the first closing portion (23) in the body portion (22). The first inlet (71) is the inflow end of the first introduction path (72). The first inlet (71) is connected to the outflow end of the first branch pipe (13b).

[0068] The first introduction path (72) is formed across the main body portion (22a) of the body portion (22) and the first disk portion (62a) of the first holding portion (62). Specifically, the first introduction path (72) radially penetrates the main body portion (22a) of the body portion (22) and then extends radially inward from the outer edge portion of the first disk portion (62a). In other words, the first introduction path (72) extends straight downward from the top of the body portion (22). The outflow end of the first introduction path (72) is connected to the inflow end of the thrust bearing cooling path (73).

[0069] The thrust bearing cooling passage (73) is a passage for cooling the thrust bearing (69a). The thrust bearing cooling passage (73) is formed along the thrust bearing (69a). In other words, the thrust bearing cooling passage (73) is formed along the bottom surface in the recess (62c) of the first disk portion (62a). The thrust bearing cooling passage (73) faces the internal space of the recess (62c) of the first disk portion (62a). The thrust bearing cooling passage (73) is a groove formed in the recess (62c). The thrust bearing cooling passage (73) extends straight radially inward from the outer edge portion of the bottom surface of the recess (62c). When the liquid refrigerant flows through the thrust bearing cooling passage (73), the liquid refrigerant touches the side surface of the thrust bearing (69a), and the thrust bearing (69a) is cooled. The outflow end of the thrust bearing cooling passage (73) is connected to the inflow end of the first radial bearing cooling passage (74).

[0070] The first radial bearing cooling passage (74) is a passage for cooling the first radial bearing (63). The first radial bearing cooling passage (74) is constituted by a spiral groove formed along the outer peripheral surface of the first radial bearing (63). The first radial bearing cooling passage (74) extends in the axial direction of the drive shaft (40). The first radial bearing cooling passage (74) is formed from the inner peripheral surface of the first disk portion (62a) of the first holding portion (62) to the inner peripheral surface of the first cylindrical portion (62b). The first radial bearing cooling passage (74) is formed between the inner peripheral surface of the first holding portion (62) and the outer peripheral surface of the first radial bearing (63). When the liquid refrigerant flows through the first radial bearing cooling passage (74), the liquid refrigerant touches the outer peripheral surface of the first radial bearing (63), and the first radial bearing (63) is cooled. The outflow end of the first radial bearing cooling passage (74) is connected to the inflow end of the first outflow passage (75).

[0071] The first outflow path (75) is a passage that penetrates the first cylindrical portion (62b) in the radial direction. The first outflow path (75) extends straight downward. The outflow end of the first outflow path (75) is the first outflow port (76). The first outflow port (76) is an opening through which the liquid refrigerant that has passed through the first refrigerant flow path (70) flows out. The first outflow port (76) is formed closer to the other axial end in the first cylindrical portion (62b). The first outflow port (76) is formed closer to the core (33) of the stator (31) than the end portion (coil end) of the coil (34) of the electric motor (30). The first outflow port (76) is located above the storage portion (27). The first outflow port (76) is located above the coil (34). In other words, the coil (34) of the electric motor (30) is disposed between the storage portion (27) and the first outflow port (76).

[0072] The liquid refrigerant flowing out from the first outflow port (76) falls onto the coil (34) due to its own weight. The liquid refrigerant that has fallen onto the coil (34) falls while cooling the coil (34) as it passes between the coils (34). The liquid refrigerant that has passed through the coil (34) further falls and is stored in the storage portion (27). Thus, since the first outflow port (76) is located above the coil (34), the coil (34) is cooled by the liquid refrigerant flowing out from the first outflow port (76).

[0073] The first outflow port (76) opens downward. By the first outflow port (76) opening downward, even if a swirling flow is generated by the rotation of the drive shaft (40) in the casing (21), the liquid refrigerant flowing out from the first refrigerant flow path (70) easily falls downward due to its own weight. Thereby, the coil (34) can be further cooled.

[0074] (4-2) Second Refrigerant Flow Path As shown in FIG. 4, the second refrigerant flow path (80) is formed in the body portion (22) of the casing (21) and the second radial bearing member (65). The second refrigerant flow path (80) cools the second radial bearing (67). The second refrigerant flow path (80) allows liquid refrigerant to flow. The second refrigerant flow path (80) includes a second inlet (81), a second introduction path (82), a second radial bearing cooling path (84), a second outflow path (85), and a second outlet (86). The second radial bearing cooling path (84) corresponds to the first flow path of the present disclosure.

[0075] The second inlet (81) is an opening for allowing liquid refrigerant to flow into the second refrigerant flow path (80). The second inlet (81) is formed at the top of the body portion (22). The second inlet (81) is formed near the second closing portion (24) in the body portion (22). The second inlet (81) is the inflow end of the second introduction path (82). The second inlet (81) is connected to the outflow end of the second branch pipe (13c).

[0076] The second introduction path (82) is formed across the main body portion (22a) of the body portion (22) and the second disk portion (66a) of the second holding portion (66). Specifically, the second introduction path (82) radially penetrates the main body portion (22a) of the body portion (22) and then extends radially inward from the outer edge portion of the second disk portion (66a). In other words, the second introduction path (82) extends straight downward from the top of the body portion (22). The outflow end of the second introduction path (82) is connected to the inflow end of the second radial bearing cooling path (84).

[0077] The second radial bearing cooling passage (84) is a passage for cooling the second radial bearing (67). The second radial bearing cooling passage (84) is constituted by a spiral groove formed along the outer peripheral surface of the second radial bearing (67). The second radial bearing cooling passage (84) extends in the axial direction of the drive shaft (40). The second radial bearing cooling passage (84) is formed from the inner peripheral surface of the second disc portion (66a) of the second holding portion (66) to the inner peripheral surface of the second cylindrical portion (66b). The second radial bearing cooling passage (84) is formed between the inner peripheral surface of the second holding portion (66) and the outer peripheral surface of the second radial bearing (67). When liquid refrigerant flows through the second radial bearing cooling passage (84), the liquid refrigerant touches the outer peripheral surface of the second radial bearing (67), and the first radial bearing (63) is cooled. The outflow end of the second radial bearing cooling passage (84) is connected to the inflow end of the second outflow passage (85).

[0078] The second outflow passage (85) is a passage that penetrates the second cylindrical portion (66b) in the radial direction. The second outflow passage (85) extends straight downward through the second cylindrical portion (66b). The outflow end of the second outflow passage (85) is the second outlet (86). The second outlet (86) is an opening through which the liquid refrigerant that has passed through the second refrigerant flow passage (80) flows out. The second outlet (86) is formed near one axial end in the second cylindrical portion (66b). The second outlet (86) is formed closer to the core (33) of the stator (31) than the end portion (coil end) of the coil (34) of the motor (30). The second outlet (86) is located above the storage portion (27). The second outlet (86) is located above the coil (34). In other words, the coil (34) of the motor (30) is disposed between the storage portion (27) and the second outlet (86).

[0079] The liquid refrigerant flowing out from the second outlet (86) drops onto the coil (34) due to its own weight. The liquid refrigerant that has dropped onto the coil (34) drops while cooling the coil (34) when passing between the coils (34). The liquid refrigerant that has passed through the coil (34) further drops and is stored in the storage portion (27). Thus, since the second outlet (86) is located above the coil (34), the coil (34) is cooled by the liquid refrigerant flowing out from the second outlet (86).

[0080] The second outlet (86) opens downward. Since the second outlet (86) opens downward, even if a swirling flow is generated by the rotation of the drive shaft (40) in the casing (21), the liquid refrigerant flowing out from the second refrigerant flow path (80) is likely to fall downward due to its own weight. Thereby, the coil (34) can be further cooled.

[0081] (4-3) Third refrigerant flow path The third refrigerant flow path (90) cools the electric motor (30). The third refrigerant flow path (90) allows a gas refrigerant to flow. The gas refrigerant flowing through the third refrigerant flow path (90) is the one obtained by vaporizing the liquid refrigerant accumulated in the storage portion (27) due to the heat of the electric motor (30). The third refrigerant flow path (90) includes a second space (S2), a gap (35) of the electric motor (30), a first space (S1), a gas discharge path (91), and a discharge port (92). The gas refrigerant flowing through the third refrigerant flow path (90) flows in the order of the second space (S2), the gap (35), the first space (S1), the gas discharge path (91), and the discharge port (92).

[0082] The gas discharge path (91) is a passage for discharging the gas refrigerant to the outside of the casing (21). The gas discharge path (91) axially penetrates the upper part of the first closing portion (23). The discharge port (92) is the outflow end of the gas discharge path (91). The discharge port (92) is formed on an end face on one axial side of the first closing portion (23). The discharge port (92) is connected to the inflow end of the return pipe (14a).

[0083] In this example, the discharge port (92) is formed only on one side surface of the electric motor (30) in the casing (21). By forming the discharge port (92) in this way, a flow is formed in which the gas refrigerant in the casing (21) flows from the other side to one side of the electric motor (30). Specifically, the gas refrigerant vaporized in the storage portion (27) flows through the gap (35) of the electric motor (30) from the second space (S2) toward the first space (S1). Thereby, the gas refrigerant passing through the gap (35) of the electric motor (30) takes away the heat of the electric motor (30), and the electric motor (30) is cooled.

[0084] (5) Flow of refrigerant Next, the flow of the refrigerant will be described with reference to FIGS. 1 and 4.

[0085] When the compressor (20) is driven and the refrigeration device (1) starts operating, as shown in FIG. 1, the liquid refrigerant flows into the branch main pipe (13a) from the downstream side of the radiator (2). The liquid refrigerant that has flowed into the branch main pipe (13a) is divided into the first branch pipe (13b) and the second branch pipe (13c).

[0086] (5-1) Flow in the first refrigerant flow path As shown by the solid line in FIG. 4, the liquid refrigerant that has flowed into the first branch pipe (13b) flows into the first refrigerant flow path (70) from the first inlet (71) of the casing (21). The liquid refrigerant that has flowed into the first inlet (71) flows downward in the first introduction path (72) and flows into the thrust bearing cooling path (73). The liquid refrigerant that has flowed into the thrust bearing cooling path (73) flows along the thrust bearing (69a). Thereby, by taking away the heat of the thrust bearing (69a), the thrust bearing (69a) is cooled.

[0087] The liquid refrigerant that has flowed out of the thrust bearing cooling path (73) flows into the first radial bearing cooling path (74). The liquid refrigerant that has flowed into the first radial bearing cooling path (74) flows from one axial side to the other side. Here, since the first radial bearing cooling path (74) is formed in a spiral shape along the outer peripheral surface of the first radial bearing (63), the entire outer peripheral surface of the radial bearings (63, 67) can be uniformly cooled.

[0088] The liquid refrigerant that has flowed out of the first radial bearing cooling path (74) flows out from the first outlet (76) via the first outflow path (75). The liquid refrigerant that has flowed out of the first outlet (76) falls onto the coil (34) of the motor (30) by its own weight and passes through the inside of the coil (34). At that time, the liquid refrigerant cools the coil (34) by taking away heat from the coil (34). The liquid refrigerant that has passed through the coil (34) further falls downward and flows into the storage portion (27) formed at the lower part of the first space (S1). Thereby, the liquid refrigerant is stored in the storage portion (27) of the first space (S1).

[0089] (5-2) Flow of the second refrigerant flow path As shown by the solid line in Fig. 4, the liquid refrigerant flowing into the second branch pipe (13c) flows into the second refrigerant flow path (80) from the second inlet (81) of the casing (21). The liquid refrigerant flowing into the second inlet (81) flows downward in the second introduction path (82) and flows into the second radial bearing cooling path (84). The liquid refrigerant flowing into the second radial bearing cooling path (84) flows from the other axial side toward one side. Here, since the second radial bearing cooling path (84) is formed in a spiral shape along the outer peripheral surface of the second radial bearing (67), the entire outer peripheral surface of the radial bearings (63, 67) can be cooled uniformly.

[0090] The liquid refrigerant flowing out from the second radial bearing cooling path (84) flows out from the second outlet (86) via the second outflow path (85). The liquid refrigerant flowing out from the second outlet (86) drops onto the coil (34) of the electric motor (30) by its own weight and passes through the inside of the coil (34). At this time, the liquid refrigerant cools the coil (34) by taking heat from the coil (34). The liquid refrigerant that has passed through the coil (34) drops further downward and flows into the storage portion (27) formed at the lower part of the second space (S2). Thereby, the liquid refrigerant is stored in the storage portion (27) of the second space (S2).

[0091] (5-3) Flow of the third refrigerant flow path The liquid refrigerant stored in the storage portion (27) of the second space (S2) vaporizes by taking the heat of the electric motor (30). Thus, as the state of the refrigerant changes, the electric motor (30) is cooled. As shown by the dashed line in Fig. 4, the gaseous refrigerant vaporized in the storage portion (27) rises in the second space (S2) and flows into the first space (S1) through the gap (35) of the electric motor (30).

[0092] At this time, the gaseous refrigerant passing through the periphery and the gap (35) of the electric motor (30) has its temperature increased by taking the heat of the electric motor (30). Thus, as the temperature of the refrigerant increases, the electric motor (30) is cooled.

[0093] The liquid refrigerant stored in the storage section (27) of the first space (S1) vaporizes by taking heat from the electric motor (30), just like the liquid refrigerant in the storage section (27) of the second space (S2). The gaseous refrigerant that has vaporized in the first space (S1) merges with the gaseous refrigerant flowing out from the second space (S2). The merged gaseous refrigerant rises within the first space (S1). At this time, the merged gaseous refrigerant further increases in temperature by taking heat from the electric motor (30). As the temperature of the refrigerant thus increases, the electric motor (30) is cooled.

[0094] The gaseous refrigerant that has risen within the first space (S1) flows into the gas discharge passage (91). The gaseous refrigerant that has flowed into the gas discharge passage (91) is discharged to the outside of the casing (21) via the discharge port (92). The gaseous refrigerant discharged from the discharge port (92) returns to the compressor (20) again via the return pipe (14a).

[0095] (6) Features (6-1) The refrigerant flow path (R) includes radial bearing cooling paths (74, 84) formed along the outer peripheral surfaces of the radial bearings (63, 67). Here, when cooling the radial bearings (63, 67) by flowing liquid refrigerant into the rotating parts of the radial bearings (63, 67), as the radial bearings (63, 67) rotate, the flowing liquid refrigerant is agitated. When the liquid refrigerant is agitated, friction occurs between the rotating parts of the radial bearings (63, 67) and the liquid refrigerant, and the loss due to this friction (so-called windage loss) increases. As a result, the loss when the drive shaft (40) rotates at high speed becomes large, and the efficiency of the compressor (20) decreases.

[0096] In contrast, in this configuration, since the radial bearing cooling paths (74, 84) are formed along the outer peripheral surfaces of the radial bearings (63, 67), the radial bearings (63, 67) can be cooled without flowing liquid refrigerant into the inside of the radial bearings (63, 67). As a result, the radial bearings (63, 67) can be cooled while suppressing an increase in windage loss caused by agitation of the liquid refrigerant.

[0097] When a gas bearing is used as the radial bearings (63, 67), in the radial bearing cooling passages (74, 84) of this configuration, since they are formed along the outer peripheral surfaces of the radial bearings (63, 67), the radial bearings (63, 67) can be cooled without causing liquid refrigerant to flow into the interiors of the radial bearings (63, 67). As a result, it is possible to cool while suppressing damage to the gas bearings serving as the radial bearings (63, 67).

[0098] (6-2) The radial bearing cooling passages (74, 84) are formed between the inner peripheral surface of the holding portions (62, 66) in the radial bearings (63, 67) and the outer peripheral surface of the radial bearings (63, 67). For this reason, the radial bearing cooling passages (74, 84) can be easily formed.

[0099] (6-3) The radial bearing cooling passages (74, 84) are formed in a spiral shape extending in the axial direction of the drive shaft (40). For this reason, the entire outer peripheral surface of the radial bearings (63, 67) can be uniformly and efficiently cooled by a single flow passage.

[0100] (6-4) The reservoir (27) is provided below the electric motor (30). For this reason, the heat of the electric motor (30) is transferred to the liquid refrigerant accumulated in the reservoir (27), and the liquid refrigerant vaporizes. Further, as the gas refrigerant vaporized in the reservoir (27) flows around the electric motor (30), the heat of the electric motor (30) is transferred to the gas refrigerant, and the temperature of the gas refrigerant rises. In this way, the electric motor (30) can be cooled by the state change and temperature change of the refrigerant.

[0101] (6-5) The outlets (76, 86) are formed above the reservoir (27). The electric motor (30) is disposed between the reservoir (27) and the outlets (76, 86). For this reason, the liquid refrigerant flowing out from the outlets (76, 86) falls by its own weight and passes through the electric motor (30). The liquid refrigerant that has passed through the electric motor (30) flows down into the reservoir (27). When the liquid refrigerant passes through the electric motor (30), the liquid refrigerant takes away the heat of the electric motor (30). As a result, the electric motor (30) can be cooled.

[0102] (6-6) The outflow ports (76, 86) open downward. Therefore, even if a swirling flow is generated in the casing (21) due to the rotation of the drive shaft (40), the liquid refrigerant easily flows downward by its own weight.

[0103] (6-7) Between the storage part (27) and the outflow ports (76, 86), the coil (34) of the electric motor (30) is arranged. Therefore, the liquid refrigerant flowing out from the outflow ports (76, 86) drops onto the coil (34) by its own weight. By passing through the coil (34), the liquid refrigerant takes away the heat of the coil (34). As a result, the coil (34) that easily generates heat can be cooled.

[0104] (6-8) The refrigerant flow path (R) includes a first refrigerant flow path (70) for cooling the first radial bearing (63) and a second refrigerant flow path (80) for cooling the second radial bearing (67). Therefore, the first radial bearing (63) can be cooled by the first refrigerant flow path (70), and the second radial bearing (67) can be cooled by the second refrigerant flow path (80).

[0105] (6-9) The refrigerant flow path (R) includes a discharge port (92) for discharging the gas refrigerant into which the liquid refrigerant has vaporized. The discharge port (92) is formed only on one side of the electric motor (30) in the casing (21). Therefore, the gas refrigerant flows from the other side to the one side of the electric motor (30) through the gap (35) formed between the stator (31) and the rotor (32) of the electric motor (30). When the gas refrigerant flows through the gap (35), the gas refrigerant takes away the heat of the electric motor (30). As a result, the electric motor (30) can be cooled.

[0106] (6-10) The refrigerant flow path (R) includes a thrust bearing cooling path (73) formed along the thrust bearing (69a). Therefore, the thrust bearing (69a) can be cooled by the liquid refrigerant flowing through the thrust bearing cooling path (73).

[0107] (7) Modified example The above-described embodiment may be modified as follows. In the following description, differences from the embodiment will be described in principle.

[0108] (7-1) Modification Example 1: Configuration of Radial Bearing Cooling Passage The radial bearing cooling passages (74, 84) may be formed linearly. In this case, the radial bearing cooling passages (74, 84) may be constituted by one flow passage extending in the axial direction along the outer peripheral surface of the radial bearings (63, 67), or may be constituted by a plurality of flow passages.

[0109] (7-2) Modification Example 2: Configuration of Bearings The radial bearings (63, 67) and the thrust bearing (69a) may be bearings other than gas bearings. For example, they may be liquid bearings, rolling bearings, sliding bearings, magnetic bearings, etc.

[0110] (7-3) Modification Example 3: Shape of Casing The protruding portion (22b) may not be provided on the body portion (22) of the casing (21). In this case, the core (33) of the stator (31) is fixed to the inner peripheral surface of the main body portion (22a) of the body portion (22). The storage portion (27) is provided in a space surrounded by the inner peripheral surface of the body portion (22), the core (33) of the stator (31), and the radial bearing members (61, 65).

[0111] (7-4) Modification Example 4: Position of Discharge Port (92) The gas discharge passage (91) and the discharge port (92) of the third refrigerant passage (90) may be formed on the surface of the casing (21) on the other end side of the motor (30). In other words, the gas discharge passage (91) and the discharge port (92) may be formed only on either one of the surface on the one end side and the surface on the other end side of the motor (30) in the casing (21).

[0112] (7-5) Modification Example 5: Other Application Examples The refrigerant passage (R) of the present disclosure may be applied to a single-stage turbo compressor (20) having one compression mechanism (50).

[0113] Although the embodiments and modifications have been described above, it will be understood that various changes in form and detail can be made without departing from the spirit and scope of the claims. Also, the above embodiments, modifications, and other embodiments may be combined or replaced as appropriate as long as the functions of the subject of the present disclosure are not impaired.

[0114] The above descriptions such as "first", "second", "third",... are used to distinguish the terms to which these descriptions are attached, and do not limit even the number and order of those terms.

Industrial Applicability

[0115] As described above, the present disclosure is useful for turbo compressors and refrigeration devices.

Explanation of Signs

[0116] 1 Refrigeration device 20 Compressor (turbo compressor) 21 Casing 27 Storage part 30 Electric motor 31 Stator 32 Rotor 33 Core 34 Coil 40 Drive shaft 62, 66 Holding part 63, 67 Radial bearing 69a Thrust bearing 70 First refrigerant flow path 73 Thrust bearing cooling path (second flow path) 74, 84 Radial bearing cooling path (first flow path) 76, 86 Outlet 80 Second refrigerant flow path 92 Discharge port R Refrigerant flow path

Claims

1. A casing (21), a stator (31) and a rotor (32), and an electric motor (30) housed inside the casing (21), a drive shaft (40) rotationally driven by the electric motor (30), radial bearings (63, 67) rotatably supporting the drive shaft (40), and a refrigerant flow path (R) through which a liquid refrigerant for cooling the radial bearings (63, 67) flows, wherein the refrigerant flow path (R) includes first flow paths (74, 84) formed along the outer peripheral surface of the radial bearings (63, 67), the refrigerant flow path (R) includes a discharge port (92) for discharging the gas refrigerant obtained by vaporization of the liquid refrigerant, and the discharge port (92) is formed only on one side of the electric motor (30) in the casing (21). Turbo compressor.

2. A casing (21), a stator (31) and a rotor (32), and an electric motor (30) housed inside the casing (21), a drive shaft (40) rotationally driven by the electric motor (30), radial bearings (63, 67) rotatably supporting the drive shaft (40), and a refrigerant flow path (R) through which a liquid refrigerant introduced from outside the turbo compressor and for cooling the radial bearings (63, 67) flows, wherein the refrigerant flow path (R) includes first flow paths (74, 84) formed along the outer peripheral surface of the radial bearings (63, 67), the liquid refrigerant flowing into the first flow path (74, 84) flows from one axial side of the drive shaft (40) to the other side, or from the other side to the one side, the first flow path (74, 84) includes an inlet end through which the liquid refrigerant flows in and an outlet end through which the liquid refrigerant flows out, and the outlet end is located on the side of the space (S1, S2) in which the electric motor (30) is disposed. Turbo compressor.

3. further comprising a holding portion (62, 66) for holding the radial bearings (63, 67), wherein the first flow path (74, 84) is formed between the inner surface of the holding portion (62, 66) and the outer peripheral surface of the radial bearings (63, 67). The turbo compressor according to claim 1 or 2.

4. The first flow path (74, 84) is formed in a spiral shape extending in the axial direction of the drive shaft (40). The turbo compressor according to any one of claims 1 to 3.

5. further comprising a storage portion (27) for storing the liquid refrigerant flowing out from the refrigerant flow path (R), wherein the drive shaft (40) extends along the horizontal direction. The storage part (27) is provided below the electric motor (30). The turbo compressor according to any one of claims 1 to 4.

6. The refrigerant flow path (R) is formed above the storage part (27) and includes outlets (76, 86) through which the liquid refrigerant flows out. The electric motor (30) is disposed between the storage part (27) and the outlets (76, 86). The turbo compressor according to claim 5.

7. The outlets (76, 86) open downward. The turbo compressor according to claim 6.

8. The stator (31) has a core (33) and a coil (34) wound around the core (33). The coil (34) is disposed between the storage part (27) and the outlets (76, 86). The turbo compressor according to claim 6 or 7.

9. The radial bearings (63, 67) are disposed on one side and the other side of the electric motor (30). The refrigerant flow path (R) includes a first refrigerant flow path (70) that cools the radial bearing (63, 67) on one side and a second refrigerant flow path (80) that cools the radial bearing (63, 67) on the other side. The turbo compressor according to any one of claims 1 to 8.

10. The refrigerant flow path (R) includes an outlet (92) for discharging the gaseous refrigerant obtained by vaporizing the liquid refrigerant. The outlet (92) is formed only on one side of the electric motor (30) in the casing (21). The turbo compressor according to claim 2.

11. The turbo compressor further includes a thrust bearing (69a) that rotatably supports the drive shaft (40). The refrigerant flow path (R) includes a second flow path (73) formed along the thrust bearing (69a). The turbo compressor according to any one of claims 1 to 10.

12. A refrigeration device including the turbo compressor (20) according to any one of claims 1 to 11.

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