JP2018123759A - Turbocompressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbocompressor having high reliability.SOLUTION: A turbocompressor (30a) comprises a rotating shaft (35), an impeller (38), a bearing (36), a discharge space (65), a pressure regulation space (67), and a communication passage (68). The impeller (38) feeds working fluid in a low-pressure space (62) in front of the impeller (38) toward a high-pressure space (63). The bearing (36) is arranged in front of the impeller (38), and rotatably supports the rotating shaft (35). The discharge space (65) is provided between the bearing (36) and the impeller (38) in an axial direction of the rotating shaft (35). The pressure regulation space (67) communicates with the low-pressure space (62) and the discharge space (65), respectively. The communication passage (68) causes the high-pressure space (63) to communicate with the pressure regulation space (67).SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a turbo compressor.

  2. Description of the Related Art Conventionally, turbo compressors that are advantageous for suppressing lubricant from flowing into impeller blades are known.

  For example, Patent Document 1 describes a turbo compressor 500 as shown in FIG. The turbo compressor 500 includes a body 502, a bearing 503, a drive shaft 504, an impeller blade 505, a rotational force generator 506, and a lubricant supply path 507. The body 502 includes a main body 521 and a shell portion 522. The main body 521 includes a working chamber 520 that functions as a motor chamber communicating with the atmosphere. The shell portion 522 has a compressor chamber 562 and a shell chamber 563. The shell chamber 563 allows the compressor chamber 562 and the space on the downstream side of the turbo compressor 500 to communicate with each other.

  In the turbo compressor 500, a ring-shaped first seal portion 509 is disposed behind the impeller blades 505. The first seal portion 509 functions as a seal portion that seals fluid (for example, gas) conveyed by the impeller blades 505. A ring-shaped second seal portion 510 is disposed behind the first seal portion 509. The second seal portion 510 suppresses the lubricant (generally lubricating oil) of the bearing 503 from being released to the impeller blades 505 or the compressor chamber 562.

  The turbo compressor 500 has an escape passage 575. The escape passage 575 includes a first opening 576, a second opening 577, and a communication passage 578. The first opening 576 is formed in a region between the first seal portion 509 and the second seal portion 510 in the axial length direction of the drive shaft 504. The second opening 577 communicates with the working chamber 520. The communication path 578 allows the first opening 576 and the second opening 577 to communicate with each other. A region between the first seal portion 509 and the second seal portion 510 is maintained at atmospheric pressure or a pressure close to atmospheric pressure. When the back pressure behind the impeller blades 505 is P1, and the pressure in the region between the first seal portion 509 and the second seal portion 510 is P2, the back pressure P1 is kept higher than the pressure P2. For this reason, the lubricant in the bearing 503 is prevented from flowing into the impeller blades 505 or the compressor chamber 562 due to the differential pressure.

JP 2008-144724 A

  Patent Document 1 does not describe disposing a bearing in front of the impeller blade 505. Therefore, the present disclosure provides a turbo compressor having high reliability when a bearing is disposed in front of an impeller.

This disclosure
A rotation axis;
An impeller fixed to the rotary shaft, wherein the impeller sends a working fluid in a low-pressure space, which is defined in the radial direction of the rotary shaft in the radial direction of the rotary shaft, toward the high-pressure space in front of the impeller. When,
A bearing disposed in front of the impeller and rotatably supporting the rotating shaft;
A discharge space that is in contact with the bearing between the bearing and the impeller in the axial direction of the rotary shaft, and stores the lubricating liquid that has flowed out of the bearing;
A pressure adjusting space communicating with the low pressure space and the discharge space at different positions; and
A communication path for communicating the high pressure space with the pressure regulating space and supplying the working fluid in the high pressure space to the pressure regulating space;
Provide turbo compressor.

  In the above turbo compressor, the bearing supports the rotating shaft rotatably in front of the impeller, but has high reliability.

Sectional drawing which shows an example of the turbo compressor of this indication The front view which shows a part of turbo compressor shown in FIG. The block diagram which shows the refrigerating cycle apparatus provided with the turbo compressor of this indication Sectional drawing which shows another example of the turbo compressor of this indication Sectional drawing which shows another example of the turbo compressor of this indication Sectional view showing a conventional turbo compressor

<Knowledge based on studies by the present inventors>
When the lubricating liquid that lubricates the bearing that rotatably supports the rotating shaft in the turbo compressor leaks toward the impeller, fatigue or erosion occurs in the impeller because the lubricating liquid collides with the impeller. As a result, the impeller is damaged, and the reliability of the turbo compressor is lowered. As described in Patent Document 1, the back pressure P1 behind the impeller blades 505 tends to increase. For this reason, if a bearing is arrange | positioned in the back of an impeller in a turbo compressor, it will be thought that lubricating liquid does not flow easily toward an impeller.

  However, depending on the operating conditions of the turbo compressor, the present inventors may arrange a bearing that rotatably supports the rotating shaft in front of the impeller from the viewpoint of appropriately supporting the rotating shaft. I found that it might be desirable. In the turbo compressor, the working fluid in the space in front of the impeller has a relatively low pressure. For this reason, when the bearing is disposed in front of the impeller, it is extremely important to prevent the lubricant from leaking toward the impeller in order to increase the reliability of the turbo compressor. Therefore, the present inventors have repeatedly investigated the technology that can prevent the lubricant from leaking toward the impeller when the bearing is disposed in front of the impeller, and devised the turbo compressor of the present disclosure. . This knowledge is based on the study by the present inventors and is not recognized as prior art.

The first aspect of the present disclosure is:
A rotation axis;
An impeller fixed to the rotating shaft, the impeller being sent toward a high-pressure space in front of the impeller, and
A bearing disposed in front of the impeller and rotatably supporting the rotating shaft;
A discharge space that is provided between the bearing and the impeller in the axial direction of the rotating shaft and stores the lubricating liquid that has flowed out of the bearing;
A pressure regulating space communicating with each of the low pressure space and the discharge space;
A communication path for communicating the high pressure space with the pressure regulating space and supplying the working fluid in the high pressure space to the pressure regulating space;
Provide turbo compressor.

  According to the first aspect, since the working fluid in the high-pressure space is supplied to the pressure regulation space through the communication path, the pressure in the pressure regulation space is higher than the pressure in the discharge space. As a result, the lubricating liquid stored in the discharge space can be prevented from leaking into the low-pressure space, and the lubricating liquid can be prevented from colliding with the impeller. As a result, fatigue or erosion can be suppressed in the impeller, and the turbo compressor according to the first aspect has high reliability.

  In addition to the first aspect, a second aspect of the present disclosure is a partition that partitions the pressure regulation space, and communicates the pressure regulation space and the low pressure space between the front end of the impeller. A turbo compressor further provided with a partition wall that defines a gap. According to the second aspect, even if the lubricating liquid passes through the pressure adjusting space and leaks into the low pressure space, the lubricating liquid flowing through the gap between the front end of the impeller and the partition wall is sheared by the rotation of the impeller. Is miniaturized. As a result, the lubricating liquid leaking into the low pressure space is unlikely to adversely affect the impeller.

  In the third aspect of the present disclosure, in addition to the first aspect or the second aspect, the width of the path that communicates the pressure regulation space with the low pressure space is greater than the width of the path that communicates the pressure regulation space with the discharge space. To provide a turbo compressor that is also large. If gas enters the inside of the bearing, the rotation shaft and the bearing are not properly lubricated, which may reduce the reliability of the turbo compressor. However, according to the third aspect, the working fluid supplied to the pressure regulation space tends to flow out toward the low pressure space. For this reason, it is difficult for the gaseous working fluid to flow into the bearing, and the turbo compressor has high reliability.

  According to a fourth aspect of the present disclosure, in addition to the first aspect or the second aspect, a turbo compressor further including a seal portion that defines at least a part of a path that communicates the pressure regulation space with the low pressure space. . According to the 4th aspect, the pressure loss of the working fluid in the path | route which connects pressure regulation space to low pressure space increases, and the outflow amount of the working fluid from pressure regulation space to low pressure space is reduced. Thereby, the working fluid tends to have a high pressure in the pressure adjusting space. For example, even when the rotational speed of the impeller is relatively low, the pressure of the working fluid in the pressure adjustment space tends to be high. As a result, the turbo compressor has higher reliability. In addition, loss due to the working fluid flowing out from the pressure regulation space into the low pressure space can be reduced, and the turbo compressor can easily exhibit high efficiency.

  In addition to any one of the first to fourth aspects, the fifth aspect of the present disclosure further includes a regulator that is disposed in the communication path and adjusts the pressure of the working fluid in the communication path. Provide turbo compressor. According to the fourth aspect, the pressure of the working fluid in the pressure adjusting space is appropriately adjusted by the regulator, and it is easy to achieve both high reliability and high efficiency in the turbo compressor.

  According to a sixth aspect of the present disclosure, in addition to any one of the first aspect to the fifth aspect, a pipe that defines the communication path and a bearing box that houses the bearing, the axis being around the axis of the rotary shaft A plurality of connecting portions arranged at predetermined intervals, and a part of the pipe is connected between the bearing case and the impeller in the axial direction of the rotating shaft. A turbo compressor arranged in a line in the axial direction of any one of the sections and the rotating shaft is provided. Surging may occur when the flow of the working fluid toward the impeller is disturbed. According to the sixth aspect, in the low-pressure space, the flow of the working fluid toward the impeller is not easily disturbed by the piping that defines the communication path, and surging is unlikely to occur. For this reason, a turbo compressor tends to exhibit high efficiency.

  In a seventh aspect of the present disclosure, in addition to any one of the first to sixth aspects, the lubricating liquid contains a substance of the same type as the main component of the working fluid as a main component. Provide a turbo compressor. According to the seventh aspect, even if the working fluid leaks from the pressure adjusting space to the discharge space and comes into contact with the lubricating liquid, the characteristics of the lubricating liquid are hardly changed. In the present specification, the “main component” means a component that is contained most on a mass basis.

  In an eighth aspect of the present disclosure, the working fluid contains, as a main component, a substance having a saturated vapor pressure lower than atmospheric pressure at normal temperature (Japanese Industrial Standard: 20 ° C. ± 15 ° C., JIS Z 8703), Provided is a turbo compressor in which the lubricating liquid contains the same kind of substance as the main component of the working fluid as a main component. According to the eighth aspect, the viscosity of the lubricating liquid tends to be relatively low, but the turbo compressor has high reliability due to the above configuration. In addition, even if the working fluid leaks from the pressure adjusting space to the discharge space and comes into contact with the lubricating liquid, the characteristics of the lubricating liquid hardly change.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In addition, the following embodiment is only an illustration of this invention and this invention is not necessarily limited by these. In the accompanying drawings, the X axis, the Y axis, and the Z axis are orthogonal to each other. The XY plane is horizontal, and the negative Z-axis direction is vertically downward (gravity direction). In the accompanying drawings, the X axis indicates the same direction, and the Y axis indicates another same direction.

  As shown in FIG. 1, the turbo compressor 30 a includes a rotary shaft 35, an impeller 38, a bearing 36 (first bearing), a discharge space 65, a pressure adjustment space 67, and a communication path 68. . The impeller 38 is fixed to the rotary shaft 35. The impeller 38 sends the working fluid in the low pressure space 62 in front of the impeller 38 toward the high pressure space 63. The bearing 36 is disposed in front of the impeller 38 (on the upstream side of the flow of the working fluid during the operation of the turbo compressor 30a). The bearing 36 supports the rotating shaft 35 rotatably. The discharge space 65 is provided between the bearing 36 and the impeller 38 in the axial direction of the rotary shaft 35. The discharge space 65 is a space for storing the lubricating liquid that has flowed out of the bearing 36. The pressure adjusting space 67 communicates with each of the low pressure space 62 and the discharge space 65. The communication path 68 is a path for communicating the high pressure space 63 with the pressure regulating space 67 and supplying the working fluid in the high pressure space 63 to the pressure regulating space 67. In other words, the communication path 68 bypasses the low pressure space 62 and connects the high pressure space 63 to the pressure regulation space 67.

  During the operation period of the turbo compressor 30 a, the working fluid in the low pressure space 62 flows toward the impeller 38 due to the rotation of the impeller 38. The working fluid flows toward the high-pressure space 63 through the compression space 61 defined around the impeller 38. The working fluid flow accelerated by the impeller 38 is then decelerated and the kinetic energy of the working fluid flow is converted to pressure energy. Thereby, the pressure of the working fluid in the high pressure space 63 becomes higher than the pressure of the working fluid in the low pressure space 62. In this way, the turbo compressor 30a compresses the working fluid. In the present specification, the high-pressure space 63 is an operation that is located downstream of the impeller 38 in the flow of the working fluid during the operation of the turbo compressor 30 a and has a pressure higher than the pressure of the working fluid in the low-pressure space 62. It means the space where fluid flows.

  During the operation period of the turbo compressor 30a, part of the working fluid flowing through the high pressure space 63 passes through the communication path 68 and is supplied to the pressure adjusting space 67, and the pressure in the pressure adjusting space 67 becomes higher than the pressure in the discharge space 65. . Thereby, it is possible to prevent the lubricating liquid stored in the discharge space 65 from leaking into the low pressure space 62. For this reason, it is possible to prevent the lubricating liquid from colliding with the impeller 38 and to suppress fatigue or erosion in the impeller 38. As a result, the turbo compressor 30a has high reliability.

  The low-pressure space 62 is defined, for example, in the radial direction of the rotation shaft 35 in front of the impeller 38 and away from the rotation shaft 35.

  As shown in FIG. 1, the turbo compressor 30 a further includes a partition wall 67 a that partitions a pressure regulating space 67, for example. The partition wall 67 a defines a gap between the pressure regulating space 67 and the low pressure space 62 between the front end of the impeller 38. In this case, even if the lubricating liquid passes through the pressure adjusting space 67 and leaks to the low pressure space 62 for some reason, the lubricating liquid flowing through the gap between the front end of the impeller 38 and the partition wall 67a is not contained in the impeller 38. It is miniaturized under the shearing force due to rotation. As a result, the lubricating liquid leaked into the low pressure space 67 is unlikely to adversely affect the impeller 38.

  The partition wall 67a has, for example, a cylindrical shape and surrounds the rotation shaft 35. A pressure regulation space 67 is defined between the partition wall 67a and the rotary shaft 35.

  As shown in FIG. 1, for example, the turbo compressor 30 a includes a pipe 68 a and a bearing box 40. The pipe 68a defines a communication path 68. A bearing 36 is accommodated in the bearing housing 40. Further, as shown in FIG. 2, the bearing housing 40 has a plurality of connecting portions 42 arranged at predetermined intervals around the axis of the rotating shaft 35. A part of the low pressure space 62 is defined between the adjacent connecting portions 42. A part of the pipe 68 a is arranged in a line in the axial direction of the rotating shaft 35 and any one of the plurality of connecting portions 42 between the bearing housing 40 and the impeller 38 in the axial direction of the rotating shaft 35. Thereby, the flow of the working fluid toward the impeller 38 is not easily disturbed by the pipe 68 a that defines the communication path 68. For this reason, surging hardly occurs and the turbo compressor 30a tends to exhibit high efficiency.

  For example, the discharge space 65 is defined between the inner surface of the bearing housing 40 and the outer surface of the rotation shaft 35. The discharge space 65 is, for example, a cylindrical space that is in contact with the rotation shaft 35. For example, a lubricant discharge path 69b is connected to the discharge space 65. The lubricating liquid discharge path 69b is a path for discharging the lubricating liquid stored in the discharge space 65 to the outside of the turbo compressor 30a.

  The pressure adjustment space 67 is defined between the discharge space 65 and the impeller 38 in the axial direction of the rotating shaft 35, for example. A path that allows the pressure regulating space 67 to communicate with the discharge space 65 extends, for example, in contact with the outer surface of the rotating shaft 35 in the axial direction of the rotating shaft 35. At least a part of the path that communicates the pressure regulating space 67 with the discharge space 65 is defined by the partition member 71. The partition member 71 is, for example, a seal ring. In this case, the seal ring is typically made of resin. A minute gap is formed between the partition member 71 and the rotary shaft 35 in the radial direction of the rotary shaft 35, and this gap forms at least a part of a path for communicating the pressure regulating space 67 with the discharge space 65. Yes. The width of the path for communicating the pressure regulating space 67 with the discharge space 65 is, for example, 50 μm to 250 μm. Here, the width of the path connecting the pressure adjusting space 67 to the discharge space 65 corresponds to the size of the gap between the partition member 71 and the rotating shaft 35 in the radial direction of the rotating shaft 35.

  The width of the path for communicating the pressure regulating space 67 with the low pressure space 62 is larger than the width of the path for communicating the pressure regulating space 67 with the discharge space 65. For example, the width of the path connecting the pressure regulation space 67 to the low pressure space 62 is 1 mm to 5 mm. Here, the width of the path that allows the pressure regulating space 67 to communicate with the low pressure space 62 corresponds to the size of the gap between the partition wall 67 a and the front end of the impeller 38 in the axial direction of the rotating shaft 35. If gas enters the inside of the bearing 36, the rotation shaft 35 and the bearing 36 are not properly lubricated, and the reliability of the turbo compressor 30a may be reduced. However, since the width of the path connecting the pressure regulating space 67 to the low pressure space 62 is larger than the width of the path communicating the pressure regulating space 67 to the discharge space 65, the working fluid supplied to the pressure regulating space 67 is low pressure space 62. Easy to leak. For this reason, it is difficult for the gaseous working fluid to flow into the bearing 36, and the turbo compressor 30a has high reliability. When the width of the path connecting the pressure regulation space 67 to the low pressure space 62 varies, this width means the minimum width. The same applies to the case where the width of the path connecting the pressure regulating space 67 to the low pressure space 62 varies.

  The pressure regulation space 67 is defined in contact with the rotating shaft 35, for example. In other words, the pressure regulation space 67 is defined between the low pressure space 62 and the rotation shaft 35 in the radial direction of the rotation shaft 35.

  For example, the low-pressure space 62 is positioned upstream of the impeller 38 in the flow direction of the working fluid, and is defined in a cylindrical shape on the radially outer side of the bearing 36.

  As shown in FIG. 1, the turbo compressor 30 a further includes, for example, a regulator 74 disposed in the communication path 68. The regulator 74 adjusts the pressure of the working fluid in the communication path 68. The pressure of the working fluid in the pressure regulation space 67 is appropriately adjusted by the regulator 74, and it is easy to achieve both high reliability and high efficiency in the turbo compressor 30a. The regulator 74 is not particularly limited as long as the pressure of the working fluid can be adjusted. For example, the regulator 74 is a valve such as a needle valve and a globe valve, an orifice, or a capillary tube.

  As shown in FIG. 1, the turbo compressor 30a further includes, for example, a casing 31a, a casing 31b, a drive motor 32, a second bearing 37, and a bearing retainer 50. An impeller 38 is accommodated in the casing 31a. A compression space 61 is defined between the inner surface of the casing 31 a and the impeller 38. The turbo compressor 30a is, for example, a centrifugal compressor. A vortex chamber is defined inside the casing 31 a on the radially outer side of the impeller 38, and at least a part of the vortex chamber forms a part of the high-pressure chamber 63.

  An impeller 38 is disposed inside the casing 31a. A bearing box 40 is disposed in front of the impeller 38 inside the casing 31a. The impeller 38 is fixed to the rotating shaft 35 by shrink fitting, for example. A part of the casing 31a has a trumpet shape having an inner diameter that expands toward the front.

  The first bearing 36 rotatably supports one end portion of the rotary shaft 35 in the axial direction in front of the impeller 38. The first bearing 36 is, for example, a slide bearing. The first bearing 36 has, for example, a sliding surface 36 a, and the sliding surface 36 a defines a lubricating space 64 for receiving the lubricating liquid between the first bearing 36 and the outer surface of the rotating shaft 35. In this case, the size of the gap (lubricating space 64) between the inner surface (sliding surface 36a) of the first bearing 36 and the outer surface of the rotary shaft 35 is such that fluid lubrication can be performed with the lubricating liquid during the operation period of the turbo compressor 30a. It has been established. The size of the gap between the inner surface of the first bearing 36 and the outer surface of the rotating shaft 35 is, for example, several tens of μm. The second bearing 37 rotatably supports the other end portion in the axial direction of the rotation shaft 35. The second bearing 37 is, for example, a slide bearing. The size of the gap between the inner surface (sliding surface) of the second bearing 37 and the outer surface of the rotating shaft 35 is also determined so that it can be fluidly lubricated with a lubricating liquid during the operation of the turbo compressor 30a.

  The first bearing 36 and the second bearing 37 are not particularly limited as long as the lubricating liquid is used, and may be, for example, a ball bearing or a roller bearing.

  The bearing retainer 50 is fixed to the bearing housing 40 in the axial direction of the rotary shaft 35. The bearing 36 is disposed between the bearing retainer 50 and the discharge space 65 in the axial direction of the rotary shaft 35. The bearing retainer 50 has a through hole extending in the axial direction, and a pipe for defining the lubricating liquid supply passage 69a is inserted into the through hole. The lubricating liquid supply path 69 a is a path for supplying the lubricating liquid toward the bearing 36. The through hole of the bearing retainer 50 is continuous with the bearing hole of the bearing 36. During the operation period of the turbo compressor 30a, the lubricating liquid is supplied to the lubricating space 64 through the lubricating liquid supply path 69a. Thereby, the lubricating space 64 is filled with the lubricating liquid.

  The casing 31 b is fixed to the casing 31 a in the axial direction of the rotation shaft 35. A drive motor 32 is accommodated in the casing 31b.

  The drive motor 32 includes a stator 33 and a rotor 34. The rotation shaft 35 extends so as to be rotatable from both ends of the drive motor 32 in the axial direction. The stator 33 and the rotor 34 are each cylindrical and are arranged concentrically. A predetermined gap exists between the outer surface of the rotor 34 and the inner surface of the stator 33, and the rotor 34 can rotate around the axis.

  The stator 33 is fixed to the inner surface of the casing 31b. The stator 33 has a configuration in which a coil is wound around an iron core that is a laminated electromagnetic steel sheet, for example. A voltage is applied to the stator 33 by an inverter (not shown). The frequency of this voltage varies. A magnetic field that is periodically switched in the rotational direction around the iron core of the stator 33 is generated by the frequency at which the voltage changes.

  The rotor 34 has a configuration in which, for example, a conductor bar made of a material such as aluminum or copper is inserted into an iron core that is a laminated electromagnetic steel sheet. In addition, the rotor 34 has a configuration in which a plurality of conductor bars are short-circuited by, for example, cylindrical end rings at both ends of the conductor bar. The rotor 34 is fixed to the rotating shaft 35 by shrink fitting, for example. The rotor 34 rotates due to electromagnetic interaction between the rotor 34 and the stator 33. A magnetic field generated by a current flowing through a coil of a stator 33 arranged around the rotor 34 causes an induced current to flow in an electric circuit formed by the conductor bar and the end ring of the rotor 34. As a result, a magnetic field is generated by the iron core of the rotor 34. In this case, an attractive force is generated between the stator 33 and the rotor 34 by the magnetic field generated by the stator 33. As a result, the rotor 34 rotates.

  The lubricating liquid contains, for example, the same type of substance as the main component of the working fluid of the turbo compressor 30a as the main component. In this case, even if the working fluid leaks from the pressure adjusting space 67 to the discharge space 65 and comes into contact with the lubricating liquid, the characteristics of the lubricating liquid hardly change.

  The working fluid of the turbo compressor 30a is not particularly limited, but contains, for example, a substance having a saturated vapor pressure lower than atmospheric pressure at room temperature as a main component. The lubricating liquid contains, for example, the same type of substance as the main component of the working fluid as a main component. In this case, the viscosity of the lubricating liquid tends to be relatively low, but the turbo compressor 30a has high reliability because of the above configuration. A substance having a saturated vapor pressure lower than atmospheric pressure at room temperature that can be a main component of the working fluid is, for example, water, alcohol, or ether.

  The pressures in the low pressure space 62, the discharge space 65, and the pressure regulation space 67 during the operation period of the turbo compressor 30a are, for example, 1 kPa, 2 kPa, and 2.5 kPa in absolute pressure, respectively.

  The turbo compressor 30a can be applied to the refrigeration cycle apparatus 10, for example. The refrigeration cycle apparatus 10 includes, for example, a turbo compressor 30a, a condenser, and an evaporator, and has a storage space 80 that stores a liquid working fluid. In the refrigeration cycle apparatus 10, a liquid working fluid is sent from the storage space 80 to the bearing 36 of the turbo compressor 30a as a lubricating liquid. As shown in FIG. 3, the refrigeration cycle apparatus 10 includes, for example, a main circuit 21, a first circulation circuit 22, a second circulation circuit 23, and a turbo compressor 30a. The refrigeration cycle apparatus 10 functions as an air conditioning apparatus dedicated to cooling, for example.

  The main circuit 21 is a circuit in which the first storage tank 24, the turbo compressor 30a, and the second storage tank 25 are connected in this order. The internal space of the first storage tank 24 and the low pressure space 62 in the turbo compressor 30a communicate with each other through the flow path 21a. The high-pressure space 63 in the turbo compressor 30a communicates with the internal space of the second storage tank 25 through the flow path 21c. The internal space of the second storage tank 25 and the internal space of the first storage tank 24 are communicated with each other by a flow path 21d.

  The first circulation circuit 22 includes a first pump 26 and a first heat exchanger 27. In the first circulation circuit 22, the liquid working fluid stored in the first storage tank 24 is supplied to the first heat exchanger 27 by the first pump 26, and the working fluid absorbed by the first heat exchanger 27 is the first. It is configured to return to the storage tank 24. In the first circulation circuit 22, the first storage tank 24 and the inlet of the first pump 26 are connected by a flow path 22a. The outlet of the first pump 26 and the inlet of the first heat exchanger 27 are connected by a flow path 22b. The outlet of the first heat exchanger 27 and the first storage tank 24 are connected by a flow path 22c.

  The second circulation circuit 23 includes a second pump 28 and a second heat exchanger 29. In the second circulation circuit 23, the liquid working fluid stored in the first storage tank 24 is supplied to the second heat exchanger 29 by the second pump 28, and the working fluid radiated by the second heat exchanger 29 is the second. It is configured to return to the storage tank 25. In the second circulation circuit 23, the second storage tank 25 and the inlet of the second pump 28 are connected by a flow path 23a. The outlet of the second pump 28 and the inlet of the second heat exchanger 29 are connected by a flow path 23b. The outlet of the second heat exchanger 29 and the second storage tank 25 are connected by a flow path 23c.

  The second storage tank 25 stores a low-temperature and high-pressure working fluid in the refrigeration cycle. The low-temperature and high-pressure working fluid is sent to the first storage tank 24 through the flow path 21d, and expands or evaporates in the first storage tank 24 to become a low-temperature and low-pressure working fluid. In the refrigeration cycle apparatus 10, the first storage tank 24 functions as an evaporator. The working fluid that has become low temperature and low pressure in the first storage tank 24 is sent to the turbo compressor 30a through the flow path 21a, compressed to high temperature and high pressure by the turbo compressor 30a, and discharged to the flow path 21c. The high-temperature and high-pressure working fluid is sent to the second storage tank 25 through the flow path 21c. The high-temperature and high-pressure working fluid flowing into the second storage tank 25 is cooled in the second storage tank 25 and becomes a low-temperature and high-pressure working fluid.

  Inside the first storage tank 24, the low-temperature and high-pressure working fluid cools the heat medium filled in the first circulation circuit 22 to become a low-temperature and low-pressure working fluid. The heat medium is sent to the first heat exchanger 27 through the flow path 22a and the flow path 22b by the operation of the first pump 26, and after the indoor air is cooled in the first heat exchanger 27, the first storage tank Returned to 24.

  The high-temperature and high-pressure working fluid flowing into the second storage tank 25 dissipates heat to the heat medium filled in the second circulation circuit 23 to become a low-temperature and high-pressure working fluid. In the refrigeration cycle apparatus 10, the second storage tank 25 functions as a condenser. The heat medium is sent to the second heat exchanger 29 through the flow path 23a and the flow path 23b by the operation of the second pump 28, radiates heat to the outdoor air in the second heat exchanger 29, and the second storage tank 25 Returned to

  The refrigeration cycle apparatus 10 functions as an air conditioner dedicated to cooling by operating as described above.

  In the refrigeration cycle apparatus 10, for example, a liquid-phase working fluid stored in the first storage tank 24 is used as a lubricating liquid to be supplied to the bearing 36. That is, the first storage tank 24 has a storage space 80 therein. The lubricating liquid supply path 69 a is connected to the first storage tank 24. The liquid-phase working fluid stored in the first storage tank 24 is supplied to the bearing 36 through the lubricating liquid supply path 69a by the operation of a pump (not shown). The lubricant that has flowed out of the bearing 36 is temporarily stored in the discharge space 65 and then discharged through the lubricant discharge path 69b. The lubricant discharge path 69b is connected to the first storage tank 24, for example. For this reason, the lubricating liquid is returned to the first storage tank 24 through the lubricating liquid discharge path 69b.

  The lubricating liquid is a liquid, the pressure loss of the flow of the lubricating liquid in the lubricating liquid discharge passage 69b is small, and the pressure in the discharge space 65 is substantially the same as the pressure in the first storage tank 24. On the other hand, since the working fluid supplied from the first storage tank 24 flows in the low pressure space 62 so as to be sucked toward the impeller 38, the pressure in the low pressure space 62 is lower than the pressure in the discharge space 65. Therefore, assuming that the discharge space 65 and the low pressure space 62 are in direct communication, the lubricating liquid that has flowed out of the bearing 36 into the discharge space 65 is scattered by the centrifugal force generated by the rotation of the rotary shaft 35, and the low pressure space is caused by the pressure difference. 62 may leak. However, the turbo compressor 30 a includes the pressure adjusting space 67, and the working fluid in the high pressure space 63 is supplied to the pressure adjusting space 67 through the communication path 68, so that the lubricating liquid leaks from the discharge space 65 to the low pressure space 62. Can be prevented.

  In the refrigeration cycle apparatus 10, for example, the liquid-phase working fluid stored in the first storage tank 24 is used as a lubricating liquid to be supplied to the second bearing 37, and the lubricating liquid supplied to the second bearing 37 is For example, it is returned to the first storage tank 24.

  The liquid-phase working fluid stored in the second storage tank 25 may be used as the lubricating liquid to be supplied to the first bearing 36 and the lubricating liquid to be supplied to the second bearing 37. A liquid-phase working fluid in the refrigeration cycle apparatus can be used as a lubricating liquid to be supplied to the first bearing 36 and a lubricating liquid to be supplied to the second bearing 37 as appropriate.

(Modification)
The turbo compressor 30a can be changed from various viewpoints. For example, the turbo compressor 30a may be changed to an axial flow type compressor or a mixed flow type compressor, or may be changed to a multistage compressor having a plurality of compression mechanisms. A centrifugal compressor is suitable for increasing the compression ratio with a small number of stages, and an axial flow compressor or a mixed flow compressor is suitable for compressing a large flow rate of working fluid. In addition to the refrigeration cycle apparatus 10, the turbo compressor 30a can be applied to, for example, an air compressor used in a plant or a large ship.

  When the turbo compressor 30a is changed to a multistage compressor, an intermediate cooler may be disposed between the impeller disposed upstream in the flow direction of the working fluid and the impeller disposed downstream. In this case, the communication path 68 is connected to the high-pressure space 63 downstream of the intermediate cooler in the flow direction of the working fluid. For this reason, the working fluid cooled by the intermediate cooler is supplied to the pressure regulation space 67. Thereby, it is possible to suppress the heat of the working fluid supplied to the pressure adjusting space 67 from being transferred to the discharge space 65 and the lubrication space 64 by heat conduction and becoming high temperature. As a result, the temperature rise of the lubricating liquid can be reduced. The intermediate cooler is not particularly limited as long as the working fluid can be cooled. For example, the intermediate cooler is constituted by a pipe that defines a flow path of a cooling heat medium.

  The turbo compressor 30a may be modified like a turbo compressor 30b shown in FIG. 4 or a turbo compressor 30c shown in FIG. The turbo compressor 30b and the turbo compressor 30c are configured similarly to the turbo compressor 30a unless otherwise described. Components that are the same as or correspond to the components of the turbo compressor 30a and the components of the turbo compressor 30b and the turbo compressor 30c are assigned the same reference numerals, and detailed descriptions thereof are omitted. The above description regarding the turbo compressor 30a also applies to the turbo compressor 30b and the turbo compressor 30c unless there is a technical contradiction.

  The turbo compressor 30 b further includes a seal portion 72 a that defines at least a part of a path that allows the pressure regulating space 67 to communicate with the low pressure space 62. The seal part 72a is a seal ring. The turbo compressor 30 c further includes a seal portion 72 b that defines at least a part of a path that allows the pressure regulating space 67 to communicate with the low pressure space 62. The seal part 72b is a labyrinth seal. The labyrinth seal that is the seal portion 72 b is defined by, for example, the wall surface of the part that defines the pressure adjustment space 67 and the impeller 38. By the seal portion 72a or the seal portion 72b, the pressure loss of the fluid flowing through the path connecting the pressure adjustment space 67 to the low pressure space 62 increases, and the amount of working fluid flowing out from the pressure adjustment space 67 to the low pressure space 62 is reduced. . Thereby, the working fluid tends to have a high pressure in the pressure adjusting space 67. For example, even when the rotational speed of the impeller 38 is relatively low, the pressure of the working fluid in the pressure adjusting space 67 tends to be high. As a result, the turbo compressor 30b and the turbo compressor 30c have higher reliability. In addition, loss due to the working fluid flowing out from the pressure regulation space 67 to the low pressure space 62 can be reduced, and the turbo compressor 30b and the turbo compressor 30c are likely to exhibit high efficiency.

  Each of the turbo compressor 30b and the turbo compressor 30c includes, for example, a regulator 74 like the turbo compressor 30a. In the turbo compressor 30b and the turbo compressor 30c, the working fluid in the pressure adjusting space 67 easily flows into the discharge space 65 by the seal portion 72a or the seal portion 72b. However, if the pressure of the working fluid supplied to the pressure regulation space 67 by the regulator 74 is made lower than the pressure in the lubrication space 64, the working fluid in the pressure regulation space 67 can easily flow into the discharge space 65, but the lubrication space 64 It is possible to prevent the working fluid from flowing in.

  The turbo compressor of the present disclosure is particularly useful for home or commercial air conditioners, chillers, and hot water supply heat pumps. The turbo compressor of the present disclosure is a large-scale refrigeration cycle device such as an industrial ice making device or a freezing / refrigeration device, a power source of pneumatic equipment used in a plant, etc., and a cleaning using compressed air used in a clean room or the like. It can also be applied to a source of compressed air in the apparatus.

30a, 30b, 30c Turbo compressor 35 Rotating shaft 36 Bearing 38 Impeller 40 Bearing box 42 Connection part 62 Low pressure space 63 High pressure space 65 Discharge space 67 Pressure regulation space 68 Communication path 68a Piping 72a, 72b Sealing part 74 Regulator

Claims (8)

A rotation axis;
An impeller fixed to the rotary shaft, the impeller for sending the working fluid in the low pressure space in front of the impeller toward the high pressure space;
A bearing disposed in front of the impeller and rotatably supporting the rotating shaft;
A discharge space that is provided between the bearing and the impeller in the axial direction of the rotating shaft and stores the lubricating liquid that has flowed out of the bearing;
A pressure regulating space communicating with each of the low pressure space and the discharge space;
A communication path for communicating the high pressure space with the pressure regulating space and supplying the working fluid in the high pressure space to the pressure regulating space;
Turbo compressor.   2. The partition wall according to claim 1, further comprising a partition wall defining the pressure control space, the partition wall defining a clearance for communicating the pressure control space and the low pressure space with a front end of the impeller. Turbo compressor.   3. The turbo compressor according to claim 1, wherein a width of a path that communicates the pressure regulation space with the low pressure space is larger than a width of a path that communicates the pressure regulation space with the discharge space.   The turbo compressor according to claim 1, further comprising a seal portion that defines at least a part of a path that communicates the pressure regulation space with the low pressure space.   The turbo compressor according to any one of claims 1 to 4, further comprising a regulator that is disposed in the communication path and adjusts the pressure of the working fluid in the communication path. Piping defining the communication path;
A bearing housing that houses the bearing, and having a plurality of connecting portions arranged at predetermined intervals around an axis of the rotating shaft,
A part of the piping is arranged in a line in the axial direction of any one of the plurality of connecting portions and the axial direction of the rotating shaft between the bearing housing and the impeller in the axial direction of the rotating shaft. The turbo compressor according to any one of 1 to 5.   The turbo compressor according to claim 1, wherein the lubricating liquid contains a substance of the same type as the main component of the working fluid as a main component. The working fluid contains as a main component a substance having a saturated vapor pressure lower than atmospheric pressure at room temperature,
The turbo compressor according to claim 1, wherein the lubricating liquid contains a substance of the same type as the main component of the working fluid as a main component.

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