JP2017223187A - Turbomachine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbomachine having high reliability.SOLUTION: A turbomachine (1a) of the disclosure includes: a rotary shaft (11); a fluid bearing (31); a bearing housing (32); a lubricant case (34); a supply pipe (40); and a pump (60). The fluid bearing (31) is a cylindrical bearing supporting the rotary shaft (11). The bearing housing (32) forms an annular space (51) for forming a squeeze film damper with an outer peripheral surface of the fluid bearing (31). The lubricant case (34) forms a storage space (34a) for storing a lubricant. The supply pipe (40) is connected with the lubricant case (34). The pump (60) is connected the supply pipe (40) and pumps the lubricant toward the storage space (34a). The fluid bearing (31) has a supply hole (52). The bearing housing (32) has a discharge hole (53).SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to turbomachines.

  In the heat pump apparatus and the refrigeration cycle apparatus, a turbo machine such as a turbo compressor that uses the kinetic energy of the rotating impeller to increase the pressure of the refrigerant may be used.

  For example, Patent Document 1 describes a heat pump device including a compression mechanism having a centrifugal impeller. The fluid (refrigerant) used in the compression-expansion cooling cycle (refrigeration cycle) of this heat pump device is water, and a water bearing is used as a bearing that supports a shaft to which a centrifugal impeller is attached. In other words, Patent Document 1 describes that the same type of fluid as the refrigerant in the refrigeration cycle is used for lubricating the bearing that supports the shaft to which the centrifugal impeller is attached.

  In addition, in a rotating device such as a motor and a generator, a bearing support structure that constitutes a squeeze film damper is known for reducing vibration of a rotating shaft.

  For example, Patent Document 2 describes a bearing support structure 300 as shown in FIG. The bearing support structure 300 includes a bearing 305 for supporting the rotating shaft 306, a bearing case 304, and a lid member 302 as a bearing housing. The bearing 305 is a ball bearing. The bearing case 304 supports the bearing 305. An oil supply path 326 is formed in the lid member 302. A first oil supply groove 341, a second oil supply groove 342, a large diameter portion 343, and an oil discharge groove 344 are formed on the outer peripheral surface of the bearing case 304. An O-ring groove 345 is formed at an intermediate position of the oil drain groove 344. Three oil drain ports 347 are formed in the circumferential direction at each of both ends of the bearing case 304. One of the three oil discharge ports 347 is formed so as to be positioned vertically upward. The oil drain port 347 opens a part of the oil drain groove 344 to the inner peripheral surface side of the bearing case 304. The bearing case 304 is elastically supported with respect to the inner peripheral surface 322 a of the cylindrical portion of the lid member 302 via an O-ring 333 fitted in the O-ring groove 345. As a result, the large-diameter portion 343 forms a slight parallel gap of about 0.1 mm with the inner peripheral surface 322a, and oil is supplied to the parallel gap to constitute a squeeze film damper.

  The oil is supplied to the first oil supply groove 341 through the oil supply path 326, further passes through the second oil supply groove 342, and is sent to the large diameter portion 343. The oil that has passed through the large diameter portion 343 reaches the oil drain groove 344. The oil that has passed through the large diameter portion 343 passes through the oil discharge port 347 and is discharged. At this time, since a part of the oil discharge port 347 is arranged vertically upward, the oil discharged through the oil discharge port 347 is supplied from directly above to the rotating shaft 306 and supplied to the bearing 305. Thereby, the oil supplied in order to acquire the effect as a squeeze film damper acts also as lubricating oil of the bearing 305 simultaneously.

JP 2001-165514 A JP2013-204740A

  In view of the techniques described in Patent Documents 1 and 2, there is room for improving the reliability of the turbomachine. Thus, the present disclosure provides a turbo machine having high reliability.

This disclosure
A rotation axis;
A cylindrical fluid bearing that has an inner peripheral surface that forms an annular gap for receiving a coolant that is a lubricant between the outer peripheral surface of the rotary shaft and supports the rotary shaft;
A bearing housing having an inner peripheral surface forming an annular space for forming a squeeze film damper with the lubricant between the outer peripheral surface of the fluid bearing and surrounding the fluid bearing;
A lubricant case that forms a storage space in which the lubricant to be supplied to the annular gap is stored;
A supply pipe connected to the lubricant case and supplying the lubricant to the storage space;
A pump connected to the supply pipe and pumping the lubricant toward the storage space;
The fluid bearing includes a first opening that contacts the storage space and a second opening that contacts the annular space, and has a supply hole extending from the first opening to the second opening,
The bearing housing has a discharge hole extending from the annular space toward the outside of the bearing housing.
Provide turbomachinery.

  The above turbomachine has high reliability.

FIG. 1 is a cross-sectional view showing a turbo machine according to the first embodiment. FIG. 2 is an enlarged cross-sectional view of a part of the turbo machine shown in FIG. FIG. 3 is a cross-sectional view showing a part of a turbo machine according to a modification. FIG. 4 is a cross-sectional view showing a turbo machine according to the second embodiment. FIG. 5 is a cross-sectional view showing a conventional bearing support structure.

<Knowledge based on studies by the present inventors>
Turbomachines such as turbocompressors are often operated at high speed. When a rotating body is rotated at a high speed in a turbo machine, the peripheral speed of the rotating shaft is high and friction loss tends to increase. In order to reduce friction loss, it is conceivable to use a low viscosity lubricant. According to the technique described in Patent Document 1, water, which is the same type of fluid as the refrigerant, is used as a bearing lubricant, and the viscosity of the bearing lubricant is considered to be low. For this reason, the technique described in Patent Document 1 is advantageous from the viewpoint of reducing friction loss. However, if a low viscosity lubricant is used, the damping coefficient of the bearing may be reduced, and the damping ratio at the critical speed corresponding to the resonance point of the turbomachine rotor may be reduced. For this reason, vibration may increase in the turbomachine. In addition, since turbomachines need to be operated at high speed, turbomachines need to be operated at many dangerous speeds, and it is necessary to suppress unstable vibrations such as oil whirls and improve bearing stability. is there.

  In order to solve these problems, it is conceivable to use a squeeze film damper as a damping mechanism. The squeeze film damper is formed in a gap between the bearing case and the bearing housing, for example, by providing a bearing case on the outer peripheral surface of the bearing and fixing the bearing to the bearing case as described in Patent Document 2. There are many cases. In Patent Document 2, it is not assumed that the technique described in Patent Document 2 is applied to a turbomachine of a refrigeration cycle, and oil is used instead of a refrigerant for lubricating the bearing 305. For this reason, the motive which combines the technique of patent document 2 with the technique of patent document 1 does not usually generate | occur | produce. However, even if the turbomachine of the refrigeration cycle is used for lubricating the bearing after supplying the same type of fluid as the refrigerant to the squeeze film damper according to the technique described in Patent Document 2, the following problems occur. Occur.

  The lubricant, which is the same type of fluid as the refrigerant, is difficult to cool the bearing when passing through the gap between the bearing housing and the bearing case. For this reason, a bearing is easy to be kept at high temperature. The refrigerant often has a boiling point lower than that of oil. For this reason, when the lubricant, which is the same type of fluid as the refrigerant, passes through the gap between the bearing and the rotary shaft, the temperature of the lubricant rises in the vicinity of the inner peripheral surface of the high-temperature bearing, and cavitation tends to occur. For this reason, the lubrication of the bearing becomes insufficient due to the occurrence of cavitation, and the bearing may be damaged. As a result, the reliability of the turbomachine may be reduced.

  The inventors have newly found such a problem, and have repeatedly studied day and night on means for solving the problem, and have devised a turbo machine of the present disclosure. In addition, said knowledge is knowledge based on examination of the present inventors, and does not necessarily admit said knowledge as prior art.

The first aspect of the present disclosure is:
A rotation axis;
A cylindrical fluid bearing that has an inner peripheral surface that forms an annular gap for receiving a coolant that is a lubricant between the outer peripheral surface of the rotary shaft and supports the rotary shaft;
A bearing housing having an inner peripheral surface forming an annular space for forming a squeeze film damper with the lubricant between the outer peripheral surface of the fluid bearing and surrounding the fluid bearing;
A lubricant case that forms a storage space in which the lubricant to be supplied to the annular gap is stored;
A supply pipe connected to the lubricant case and supplying the lubricant to the storage space;
A pump connected to the supply pipe and pumping the lubricant toward the storage space;
The fluid bearing includes a first opening that contacts the storage space and a second opening that contacts the annular space, and has a supply hole extending from the first opening to the second opening,
The bearing housing has a discharge hole extending from the annular space toward the outside of the bearing housing.
Provide turbomachinery.

  According to the first aspect, the lubricant stored in the storage space whose pressure has been increased by the pump is supplied to the annular gap between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the fluid bearing, and the liquid film is formed. Form and lubricate fluid bearings. In addition, the lubricant stored in the storage space is supplied to the annular space through the supply hole, and after forming the squeeze film damper, the lubricant is discharged through the discharge hole. Thus, since the lubricant passes through the supply hole before being supplied to the annular space, the amount of heat transferred from the fluid bearing to the lubricant is large, and the fluid bearing is in a state in which the temperature rise of the fluid bearing is suppressed. The heat balance at is easy to stabilize. As a result, the temperature of the lubricant that is supplied to the annular gap between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the fluid bearing and forms a liquid film is easily kept below the boiling point, and the occurrence of cavitation is suppressed. Thus, the fluid bearing can be lubricated well. As a result, the turbomachine of the first aspect has high reliability.

  According to a second aspect of the present disclosure, in addition to the first aspect, the supply hole includes the first opening inside the second opening in a radial direction of the fluid bearing, and is on the axis of the fluid bearing. A turbomachine having an axis inclined with respect to the same is provided. According to the second aspect, the vicinity of the inner peripheral surface of the fluid bearing can be effectively cooled by the lubricant passing through the supply hole. For this reason, the temperature rise of the lubricant in the annular gap can be suppressed. In addition, processing for forming the supply hole in the fluid bearing is easy.

  In addition to the first aspect or the second aspect, the third aspect of the present disclosure further includes an impeller fixed to the rotary shaft in a suction space formed away from the fluid bearing in the axial direction of the rotary shaft. The bearing housing has a partition wall that is adjacent to the end surface of the fluid bearing on the impeller side and forms a discharge space that communicates with the suction space, and the discharge hole opens into the discharge space. Provide turbomachinery. The lubricant in the discharge hole has a pressure higher than the pressure of the refrigerant in the suction space by the action of the pump. Since the discharge space communicates with the suction space, the lubricant is discharged from the discharge hole into the discharge space due to the difference between the pressure of the lubricant in the discharge hole and the pressure of the refrigerant in the suction space. Further, the flow rate of the lubricant in the supply hole, the annular space, and the discharge hole increases due to the difference between the pressure of the lubricant in the discharge hole and the pressure of the refrigerant in the suction space. For this reason, the amount of heat transferred from the fluid bearing to the lubricant is large, and the heat balance in the fluid bearing is likely to be stabilized in a state where the temperature rise of the fluid bearing is suppressed more reliably. As a result, the temperature of the lubricant that is supplied to the annular gap between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the fluid bearing and forms a liquid film is more easily maintained below the boiling point. Generation can be suppressed more reliably. For this reason, a fluid bearing can be lubricated more reliably and reliably. As a result, the turbomachine of the third aspect has high reliability.

The fourth aspect of the present disclosure is:
A method of operating a turbomachine,
(I) providing a turbomachine according to any one of the first to third aspects;
(Ii) rotating the rotating shaft;
(Iii) operating the pump to pump the lubricant into the storage space;
(Iv) supplying the lubricant to the annular space by passing the supply hole from the storage space by the pressure of the lubricant increased by the pump;
(V) discharging the lubricant from the annular space to the outside of the fluid bearing through the discharge hole;
Provide a method.

  According to the fourth aspect, the turbo machine according to the first to third aspects can exhibit high reliability.

The fifth aspect of the present disclosure includes, in addition to the fourth aspect,
In (i), the turbomachine of the third aspect is provided,
The lubricant in the discharge hole has a pressure higher than the pressure of the refrigerant in the suction space by increasing the pressure of the lubricant by the pump.
In (v), due to the difference between the pressure of the lubricant in the discharge hole and the pressure of the refrigerant in the suction space, the lubricant is discharged from the annular space through the discharge hole to the discharge space.
Provide a method.

  According to the fifth aspect, the turbo machine of the third aspect can exhibit high reliability more reliably.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description relates to an example of the present invention, and the present invention is not limited to these.

<First Embodiment>
As shown in FIG. 1, the turbo machine 1 a according to the first embodiment includes a rotating shaft 11, a fluid bearing 31, a bearing housing 32, a lubricant case 34, a supply pipe 40, and a pump 60. . The turbo machine 1a is typically used for a refrigeration cycle. The turbo machine 1a is typically a turbo compressor. In some cases, the turbo machine 1a may be a turbine that generates rotational power from the energy of the refrigerant and reduces the pressure of the refrigerant. Hereinafter, the turbo machine 1a will be described taking the case where the turbo machine 1a is a turbo compressor as an example.

  The fluid bearing 31 is a cylindrical component that has an inner peripheral surface that forms an annular gap 50 that receives a coolant, which is a lubricant, between the outer peripheral surface of the rotary shaft 11 and supports the rotary shaft 11. The bearing housing 32 has an inner peripheral surface that forms an annular space 51 for forming a squeeze film damper with a lubricant between the outer periphery of the fluid bearing 31 and surrounds the fluid bearing 31. The lubricant case 34 forms a storage space 34a in which the lubricant is stored. The supply pipe 40 is connected to the lubricant case 34. The supply pipe 40 is a pipe for supplying a lubricant to the storage space 34a. The pump 60 is connected to the supply pipe 40 and pumps the lubricant toward the storage space 34a. The fluid bearing 31 has a supply hole 52. The supply hole 52 includes a first opening 52a in contact with the storage space 34a and a second opening 52b in contact with the annular space 51, and extends from the first opening 52a to the second opening 52b. The bearing housing 52 has a discharge hole 53. The discharge hole 53 extends from the annular space 51 toward the outside of the bearing housing 32.

  The hydrodynamic bearing 31, the bearing housing 32, the lubricant case 34, the supply pipe 40, and the pump 60 constitute a bearing device 30a.

  The turbo machine 1a is operated by a method including the following steps (i) to (v), for example. (I) The turbo machine 1a is provided. (Ii) The rotating shaft 11 is rotated. (Iii) The pump 60 is operated to pump the lubricant into the storage space 34a. (Iv) The lubricant is supplied to the annular space 51 through the supply hole 52 from the storage space 34 a by the pressure of the lubricant increased by the pump 60. (V) The lubricant is discharged out of the fluid bearing 31 through the discharge hole 53 from the annular space 51.

  In the turbo machine 1a, a part of the refrigerant in the refrigeration cycle is pumped by the pump 60 toward the storage space 34a. The refrigerant pumped to the storage space 34a is typically in a liquid state. The pump 60 is connected to a component such as an evaporator or a condenser of a refrigeration cycle in which a refrigerant liquid is stored by piping. The arrows in FIG. 2 conceptually show the flow of the lubricant. As shown in FIG. 2, the liquid refrigerant stored in the storage space 34 a is supplied to the annular gap 50 as a lubricant by having a pressure increased by the pump 60. The dimension in the radial direction of the annular gap 50 is determined so that fluid lubrication is possible for the rotating shaft 11 and the fluid bearing 31. The lubricant supplied to the annular gap 50 takes the heat generated by the rotation of the rotary shaft 11 through the annular gap 50 and is discharged from the annular gap 50. Thus, in the turbo machine 1a, typically, the refrigerant of the refrigeration cycle is used as the lubricant. Thereby, the fluid bearing 31 supports the rotating shaft 11 at least in the radial direction.

  As shown in FIG. 2, a part of the lubricant that is a liquid refrigerant stored in the storage space 34 a is supplied to the annular space 51 through the supply hole 52 by having a pressure increased by the pump 60. Forming a squeeze film damper. Thereafter, the lubricant is discharged from the annular space 51 through the discharge hole 53. The viscosity of the lubricant, which is a refrigerant, is usually lower than that of the lubricating oil. In the turbo machine 1a, since the squeeze film damper is formed in the annular space 51 in this way, it is possible to suppress a decrease in the damping performance due to the low viscosity of the lubricant, and when the rotating shaft 11 rotates at a critical speed. However, vibration is unlikely to occur in the turbo machine 1a.

  In addition, since the lubricant passes through the supply hole 52 before being supplied to the annular space 51, the amount of heat transferred from the fluid bearing 31 to the lubricant is large, and the temperature rise of the fluid bearing 31 is suppressed. Therefore, the heat balance in the fluid bearing 31 is likely to be stable. As a result, the temperature of the lubricant that is supplied to the annular gap 50 between the outer peripheral surface of the rotating shaft 11 and the inner peripheral surface of the fluid bearing 31 to form a liquid film is easily kept below the boiling point, and the cavitation Generation | occurrence | production is suppressed and the fluid bearing 31 can be lubricated favorably. As a result, the turbo machine 1a can exhibit high reliability.

  As shown in FIG. 2, the supply hole 52 includes a first opening 52 a inside the second opening 52 b in the radial direction of the fluid dynamic bearing 31. The supply hole 52 includes, for example, a first portion extending in the axial direction of the fluid bearing 31 from the first opening 52a and a second portion extending in the radial direction toward the second opening 52, and the first portion and the second portion are It is connected in the middle of the supply hole 52.

  The lubricant is not particularly limited as long as it is the same type of fluid as the refrigerant of the refrigeration cycle, but is, for example, water.

  As shown in FIG. 2, the bearing device 30 a further includes, for example, an elastic member 33. A plurality of (for example, two) elastic members 33 are disposed apart from each other in the axial direction of the fluid bearing 31 between the outer peripheral surface of the fluid bearing 31 and the inner peripheral surface of the bearing housing 32. Thereby, an annular space 51 for forming a squeeze film damper is formed between two elastic members 33 adjacent to each other in the axial direction of the fluid bearing 31. Further, the fluid bearing 31 is appropriately held inside the bearing housing 32 by the elastic member 33. The elastic member 33 is, for example, an O-ring made of synthetic rubber. A groove for accommodating a part of the elastic member 33 may be formed on at least one of the outer peripheral surface of the fluid bearing 31 and the inner peripheral surface of the bearing housing 32.

  As shown in FIG. 1, the turbo machine 1 a further includes, for example, an impeller 12, a housing 20, and an electric motor 80. The bearing housing 32 is attached to the housing 20 inside the housing 20. A suction space 71 is formed inside the housing 20. The suction space 71 is formed away from the fluid bearing 31 in the axial direction of the rotary shaft 11. As shown in FIG. 2, the bearing housing 32 includes, for example, an outer edge portion 32a, an inner edge portion 32b, and a plurality of connecting portions 32c. The outer edge portion 32 a has a cylindrical shape and is attached to the housing 20. The inner edge portion 32 b is cylindrical and is formed on the radially inner side with respect to the outer edge portion 32 a and has an inner peripheral surface that forms the annular space 51. The plurality of connecting portions 32c are arranged at predetermined intervals in the circumferential direction, and connect the outer edge portion 32a and the inner edge portion 32b. Each of the plurality of connecting portions 32c is columnar. A suction path 72 for supplying the refrigerant toward the suction space 71 is formed by a space formed between the adjacent connecting portions 32c.

  As shown in FIG. 1, the housing 20 has a communication hole 54. The communication hole 54 is continuous with the discharge hole 53 and extends toward the outside of the turbo machine 1a. Thereby, the lubricant supplied to the annular space 51 can be discharged to the outside of the turbo machine 1a.

  As shown in FIG. 1, the impeller 12 is fixed to the rotating shaft 11 in the suction space 71. For example, the fluid bearing 31 is disposed at a position closer to the end of the rotary shaft 11 than the impeller 12 in the axial direction of the rotary shaft 11. Although one impeller 12 is shown in FIG. 1, a plurality of stages of impellers 12 may be fixed to the rotating shaft 11.

  The rotating shaft 11 is, for example, a solid cylindrical member extending in the horizontal direction. The rotating shaft 11 and the impeller 12 form a rotating body 10. The rotating shaft 11 includes, for example, a straight portion and a tapered portion. The straight portion has a certain radius in the axial direction of the rotating shaft 11. The taper portion has a radius that decreases toward the end of the rotation shaft 11 in the axial direction of the rotation shaft 11. The taper portion extends from the end of the straight portion to the end of the rotating shaft 11 in the axial direction of the rotating shaft 11.

  The inner peripheral surface of the fluid bearing 31 faces, for example, a taper portion of the rotating shaft 11 and a part of a straight portion in contact with the taper portion. The inner peripheral surface of the fluid bearing 31 forms, for example, a straight hole and a tapered hole. The straight hole has a constant radius in the axial direction of the fluid bearing 31. The tapered hole extends continuously from the straight hole and has a radius that decreases as the distance from the straight hole increases. Thereby, the rotating shaft 11 can be supported in a radial direction and a thrust direction.

  The lubricant case 34 is disposed, for example, on the opposite side of the impeller 12 when viewed from the fluid bearing 31 in the axial direction of the fluid bearing 31. For example, as shown in FIG. 2, the lubricant case 34 is a bowl-shaped case that opens in a specific direction, and the edge of the lubricant case 34 is fixed to the inner edge portion 32 b of the bearing housing 32. For example, the end of the rotating shaft 11 and the end surface of the fluid bearing 31 in the axial direction are in contact with the storage space 34a. The first opening 52a is formed, for example, on the end surface of the fluid bearing 31 in the axial direction.

  The supply pipe 40 extends through the lubricant case 34, and one end of the supply pipe 40 opens into the storage space 34a. The other end of the supply pipe 40 is connected to a discharge port of the pump 60, for example. The supply pipe 40 is configured by a single pipe or a plurality of pipes connected in series.

  As shown in FIG. 1, the electric motor 80 includes a rotor 81, a stator 82, and a stator housing 83. The rotor 81 is a cylindrical member, and is fixed to the rotating shaft 11 by “shrink fitting”. The stator 82 is a cylindrical member, and a gap having a predetermined interval is formed between the inner peripheral surface of the stator 82 and the outer peripheral surface of the rotor 81. The outer peripheral surface of the stator 82 is fixed to the stator housing 83. The end surface of the stator housing 83 in the axial direction is fixed to the end surface of the housing 20 in the axial direction, for example. The rotor 81 may be fixed to the rotating shaft 11 by using, for example, a coupling instead of “shrink fitting”.

  When the electric motor 80 operates, the rotating body 10 rotates. Thus, the refrigerant flows into the suction space 71 through the suction path 72 and is guided to the impeller 12. The refrigerant introduced into the impeller 12 is given kinetic energy in the process of passing through the impeller 12. Thereafter, the kinetic energy of the refrigerant that has passed through the impeller 12 is converted into pressure energy, thereby compressing the refrigerant.

  Although the operating conditions of the turbo machine 1a are not particularly limited, for example, the refrigerant pressure is negative in the suction space 71. In other words, the pressure of the refrigerant in the suction space 71 is an absolute pressure lower than the atmospheric pressure.

(Modification)
The turbo machine 1a can be changed from various viewpoints. For example, the bearing device 30a of the turbo machine 1a may be changed to a bearing device 30b shown in FIG. The bearing device 30b is configured in the same manner as the bearing device 30a unless otherwise described. Components of the bearing device 30b that are the same as or correspond to those of the bearing device 30a are assigned the same reference numerals, and detailed descriptions thereof are omitted. The description regarding the bearing device 30a also applies to the bearing device 30b unless there is a technical contradiction.

  As shown in FIG. 3, in the bearing device 30 b, the supply hole 52 includes a first opening 52 a inside the second opening 52 b in the radial direction of the fluid bearing 31 and is inclined with respect to the axis of the fluid bearing 31. Has an axis. Thereby, a part of the supply hole 52 is formed near the inner peripheral surface of the fluid bearing 31, so that the vicinity of the inner peripheral surface of the fluid bearing 31 can be effectively cooled by the lubricant passing through the supply hole 52. For this reason, the temperature rise of the lubricant in the annular gap 50 can be suppressed. Further, since the supply hole 52 may be formed in a certain direction from the first opening 52a to the second opening 52b, the number of steps required for switching the drilling direction of the fluid bearing 31 for forming the supply hole 52 can be reduced. That is, according to the bearing device 30b, the processing for forming the supply hole 52 in the fluid bearing 31 is easy.

Second Embodiment
Next, a turbo machine 1b according to the second embodiment will be described. The turbo machine 1b is configured similarly to the turbo machine 1a unless otherwise described. Components of the turbo machine 1b that are the same as or correspond to the turbo machine 1a are denoted by the same reference numerals, and detailed description thereof is omitted. The description regarding the first embodiment also applies to the second embodiment as long as there is no technical contradiction.

  The turbo machine 1b includes a bearing device 30c instead of the bearing device 30a. As shown in FIG. 4, the turbo machine 1 b further includes an impeller 12. The impeller 12 is fixed to the rotary shaft 11 in a suction space 71 formed away from the fluid bearing 31 in the axial direction of the rotary shaft 11. The bearing housing 32 of the bearing device 30 c has a partition wall 35. The partition wall 35 forms a discharge space 55. The discharge space 55 is a space adjacent to the end surface of the hydrodynamic bearing 31 on the impeller 12 side and communicating with the suction space 71.

  For example, the bearing housing 32 protrudes closer to the impeller 12 side than the end surface of the fluid bearing 31 on the impeller 12 side in the axial direction of the fluid bearing 31. The partition wall 35 extends, for example, in the radial direction of the fluid bearing 31 at the end of the bearing housing 32 on the impeller 12 side. The partition wall 35 has a through hole having a hole diameter slightly larger than the diameter of the rotating shaft 11, and the rotating shaft 11 is inserted into the through hole. An annular gap 35 a is formed between the outer peripheral surface of the rotating shaft 11 and the inner peripheral surface forming the through hole of the partition wall 35. As a result, the discharge space 55 communicates with the suction space 71. In addition, the partition wall 35 prevents the lubricant guided to the discharge space 55 from entering the suction space 71 through the annular gap 35a in the liquid state. The radial width of the annular gap 35 a is, for example, larger than the radial width of the annular gap 50, but is set to a size that can prevent the liquid lubricant from entering the suction space 71. ing. Thereby, it can prevent that a liquid collides with the rotating impeller 12 and the impeller 12 is damaged. In addition, as long as the rotating shaft 11 does not contact with the partition wall 35, a gap other than an annular shape may be formed between the outer peripheral surface of the rotating shaft 11 and the inner peripheral surface forming the through hole of the partition wall 35.

  The turbo machine 1b is operated by a method including the following steps in the same manner as the turbo machine 1a. (I) A turbo machine 1b is provided. (Ii) The rotating shaft 11 is rotated. (Iii) The pump 60 is operated to pump the lubricant into the storage space 34a. (Iv) The lubricant is supplied to the annular space 51 through the supply hole 52 from the storage space 35 a by the pressure of the lubricant increased by the pump 60. (V) The lubricant is discharged out of the fluid bearing 31 through the discharge hole 53 from the annular space 51. Here, the lubricant in the discharge hole 53 has a pressure higher than that of the refrigerant in the suction space 71 because the pressure of the lubricant is increased by the pump 60. In addition, in (v), due to the difference between the pressure of the lubricant in the discharge hole 53 and the pressure of the refrigerant in the suction space 71, the lubricant is discharged from the annular space 51 through the discharge hole 53 to the discharge space 55.

  Thus, the lubricant is discharged from the discharge hole 53 to the discharge space 55 due to the difference between the pressure of the lubricant in the discharge hole 53 and the pressure of the refrigerant in the suction space 71. Further, due to the difference between the pressure of the lubricant in the discharge hole 53 and the pressure of the refrigerant in the suction space 71, the flow rate of the lubricant in the supply hole 52, the annular space 51, and the discharge hole 53 increases. For this reason, the amount of heat transferred from the fluid bearing 31 to the lubricant is large, and the heat balance in the fluid bearing 31 is likely to be stabilized in a state where the temperature rise of the fluid bearing 31 is more reliably suppressed. As a result, the temperature of the lubricant that is supplied to the annular gap 50 between the outer peripheral surface of the rotating shaft 11 and the inner peripheral surface of the fluid bearing 31 to form a liquid film can be more reliably maintained below the boiling point. The occurrence of cavitation can be more reliably suppressed. For this reason, the fluid bearing 31 can be more reliably and reliably lubricated. As a result, the turbo machine 1b has high reliability.

  For example, the annular gap 50 opens into the discharge space 55. Accordingly, the lubricant that has lubricated the rotary shaft 11 and the fluid bearing 31 through the annular gap 50 is guided to the discharge space 55.

  As shown in FIG. 4, the bearing housing 32 further has a discharge hole 56. The discharge hole 56 is a hole extending from an opening in contact with the discharge space 55 to an opening in contact with the external space of the bearing housing 32. As a result, the lubricant guided to the discharge space 55 through the annular gap 50 or the discharge hole 53 can be discharged from the discharge hole 56 to the outside of the bearing housing 32 and thus to the outside of the turbo machine 1b.

  The turbo machine of the present disclosure is useful for a heat pump, a refrigerator, and an air conditioner.

1a, 1b Turbomachine 11 Rotating shaft 12 Impeller 31 Fluid bearing 32 Bearing housing 34 Lubricant case 35 Bulkhead 40 Supply pipe 50 Annular gap 51 Annular space 52 Supply hole 52a First opening 52b Second opening 53 Discharge hole 55 Discharge space 60 Pump 71 Suction space

Claims (5)

A rotation axis;
A cylindrical fluid bearing that has an inner peripheral surface that forms an annular gap for receiving a coolant that is a lubricant between the outer peripheral surface of the rotary shaft and supports the rotary shaft;
A bearing housing having an inner peripheral surface forming an annular space for forming a squeeze film damper with the lubricant between the outer peripheral surface of the fluid bearing and surrounding the fluid bearing;
A lubricant case that forms a storage space in which the lubricant to be supplied to the annular gap is stored;
A supply pipe connected to the lubricant case and supplying the lubricant to the storage space;
A pump connected to the supply pipe and pumping the lubricant toward the storage space;
The fluid bearing includes a first opening that contacts the storage space and a second opening that contacts the annular space, and has a supply hole extending from the first opening to the second opening,
The bearing housing has a discharge hole extending from the annular space toward the outside of the bearing housing.
Turbo machine.   2. The turbo according to claim 1, wherein the supply hole includes the first opening inside the second opening in a radial direction of the fluid bearing, and has an axis inclined with respect to the axis of the fluid bearing. machine. An impeller fixed to the rotary shaft in a suction space formed away from the fluid bearing in the axial direction of the rotary shaft;
The bearing housing has a partition wall that forms a discharge space that is adjacent to the end surface of the fluid bearing on the impeller side and communicates with the suction space;
The turbomachine according to claim 1, wherein the discharge hole is open to the discharge space. A method of operating a turbomachine,
(I) providing the turbomachine according to any one of claims 1 to 3,
(Ii) rotating the rotating shaft;
(Iii) operating the pump to pump the lubricant into the storage space;
(Iv) supplying the lubricant to the annular space by passing the supply hole from the storage space by the pressure of the lubricant increased by the pump;
(V) discharging the lubricant from the annular space to the outside of the fluid bearing through the discharge hole;
Method. In (i), the turbomachine according to claim 3 is provided,
The lubricant in the discharge hole has a pressure higher than the pressure of the refrigerant in the suction space by increasing the pressure of the lubricant by the pump.
In (v), due to the difference between the pressure of the lubricant in the discharge hole and the pressure of the refrigerant in the suction space, the lubricant is discharged from the annular space through the discharge hole to the discharge space.
The method of claim 4.

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