JP2007056710A - Turbine unit for air cycle refrigeration and cooling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbine unit for air cycle refrigeration and cooling in which a detection means for thrust acting on a main shaft has a simple construction and high reliability, stable high-speed rotation is obtained while keeping a minimal clearance of impellers, bearings for supporting the main shaft are improved in long-term durability, long-life and reliability and operation status of an air cycle refrigeration and cooling system can be monitored. <P>SOLUTION: The turbine unit 5 for air cycle refrigeration and cooling has a compressor 6 and an expansion turbine 7. The compressor impeller 6a and the turbine impeller 7a are respectively attached to both ends of the main shaft 13 and the compressor impeller 6a is driven with power generated at the turbine impeller 7a. The main shaft 13 is supported by the roller bearings 15, 16 in a radial direction. The thrust acting on the main shaft 13 is supported by electromagnets 17. Pressure sensors 61-64 are provided as an air pressure measurement means for measuring air pressure of at least one of the compressor 6 and the expansion turbine 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air cycle refrigeration cooling turbine unit of an air cycle refrigeration cooling system in which air is used as a refrigerant and is used for a refrigeration warehouse, a low temperature room of 0 ° C. or less, and air conditioning.

  The use of air as a refrigerant is preferable in terms of environmental protection and safety compared to the case of using chlorofluorocarbon or ammonia gas, but is insufficient in terms of characteristics as energy efficiency. However, when used in a facility that can directly blow in air, such as a refrigerated warehouse, the total cost can be reduced to the same level as existing systems by taking measures such as omitting the internal fan and defrost. there is a possibility. At present, the use of chlorofluorocarbon as a refrigerant is already restricted from the environmental viewpoint, and it is desired to avoid using other refrigerant gas as much as possible. Therefore, an air cycle refrigeration cooling system that uses air as a refrigerant has been proposed for the above-described applications (for example, Patent Document 1 and Non-Patent Document 1).

Further, it is stated that the theoretical efficiency of air cooling is equal to or higher than that of chlorofluorocarbon or ammonia gas in a deep coal region of −30 ° C. to −60 ° C. (Non-patent Document 1). However, it is also stated that obtaining the theoretical efficiency of the air cooling is not possible until there is an optimally designed peripheral device. The peripheral device is a compressor, an expansion turbine, or the like.
As the compressor and the expansion turbine, a turbine unit in which a compressor impeller and an expansion turbine impeller are attached to a common main shaft is used (Patent Document 1, Non-Patent Document 1).

In addition, as a turbine compressor which processes process gas, a turbine impeller is attached to one end of the main shaft, a compressor impeller is attached to the other end, and the main shaft is supported by a journal and a thrust bearing that is controlled by an electromagnet current. A compressor has been proposed (Patent Document 2).
In addition, although it is a proposal for a gas turbine engine, in order to avoid the thrust load acting on the rolling bearing for supporting the main shaft from shortening the bearing life, the thrust load acting on the rolling bearing should be reduced by the thrust magnetic bearing. Has been proposed (Patent Document 3).
Japanese Patent No. 2623202 Japanese Patent Application Laid-Open No. 7-91760 JP-A-8-261237 Magazine, Nikkei Mechanical, “Cooling the Air with Air”, published November 13, 1995, no 467, pp. 46-52

As described above, as the air cycle refrigeration cooling system, in order to obtain the theoretical efficiency of air cooling that is highly efficient in the deep coal region, an optimally designed compressor and expansion turbine are required.
As the compressor and the expansion turbine, a turbine unit in which the compressor wheel and the expansion turbine wheel are attached to a common main shaft as described above is used. In this turbine unit, the compressor impeller can be driven by the power generated by the expansion turbine, thereby improving the efficiency of the air cycle refrigerator.

However, in order to obtain practical efficiency, it is necessary to keep the gap between each impeller and the housing minute. The fluctuation of the gap hinders stable high-speed rotation and causes a decrease in efficiency.
In addition, a thrust force acts on the main shaft by the air acting on the compressor impeller and the turbine impeller, and a thrust load is applied to the bearing that supports the main shaft. The rotation speed of the main shaft of the turbine unit in the air cooling turbine unit is 80,000 to 100,000 rotations per minute, which is very high compared to a bearing for general use. For this reason, the thrust load as described above causes a decrease in long-term durability and life of the bearing supporting the main shaft, and decreases the reliability of the turbine unit for air cycle refrigeration cooling. Unless the problem of long-term durability of such a bearing is solved, it is difficult to put the air cycle refrigeration cooling turbine unit into practical use, and hence the air cycle refrigeration cooling system into practical use. However, the techniques disclosed in Patent Document 1 and Non-Patent Document 2 have not yet been solved with respect to a decrease in the long-term durability of the bearing against a thrust load under high-speed rotation.

  In the case where the main shaft is supported by a journal bearing made of a magnetic bearing and a thrust bearing, such as the magnetic bearing type turbine compressor of Patent Document 2, the journal bearing does not have a restriction function in the axial direction. For this reason, if there is an unstable factor in controlling the thrust bearing, it is difficult to perform stable high-speed rotation while maintaining a minute gap between the impeller and the housing. In the case of a magnetic bearing, there is also a problem of contact when the power is stopped.

  The object of the present invention is that the structure of the means for detecting the thrust force acting on the main shaft is simple and reliable, stable high-speed rotation is obtained while maintaining a minute gap of the impeller, and the long-term durability of the bearing supporting the main shaft It is intended to provide an air cycle refrigeration cooling turbine unit that can improve the service life, extend the service life and improve the reliability, and can monitor the operation status of the air cycle refrigeration cooling system.

  The air cycle refrigeration cooling turbine unit of the present invention is an air cooling turbine unit having a compressor and an expansion turbine, and the compressor impeller of the compressor and the turbine impeller of the expansion turbine are respectively attached to both ends of the main shaft. The compressor wheel is driven by the power generated by the turbine wheel, the main shaft is supported by a rolling bearing in the radial direction, the thrust force applied to the main shaft is supported by an electromagnet, the compressor and the expansion An air pressure measuring means for measuring the air pressure of at least one of the turbines is provided. The rolling bearing preferably has a function of holding the axial position between the inner and outer rings, such as a deep groove ball bearing. An angular ball bearing may be used.

The turbine unit for air cycle refrigeration cooling of this structure cools the air used as a cooling medium with a heat exchanger in an air cycle refrigeration cooling system. The air cooled by the heat exchanger is used to be cooled and discharged by adiabatic expansion to a target temperature, for example, a very low temperature of about −30 ° C. to 60 ° C. by an expansion turbine.
In this turbine unit, the compressor impeller and the turbine impeller of the expansion turbine are attached to a common main shaft, and the compressor impeller is driven by the power generated by the turbine impeller, so a power source is unnecessary and compact. It can cool efficiently with a simple structure.
In order to ensure the efficiency of compression and expansion of the turbine unit, it is necessary to keep the gap between each impeller and the housing minute. In the air cycle refrigeration cooling system, ensuring this efficiency is important. On the other hand, since the main shaft of the impeller is supported by a rolling bearing, the main shaft position is regulated to some extent by the axial position control function of the rolling bearing, and a small gap between each impeller and the housing is kept constant. Can do.
However, a thrust force is applied to the main shaft of the turbine unit due to air pressure acting on each impeller. Further, in a turbine unit used in an air cooling system, the rotation speed is very high, for example, about 80,000 to 100,000 rotations per minute. For this reason, when the thrust force acts on a rolling bearing that rotatably supports the main shaft, the long-term durability of the bearing decreases.

In the present invention, since the thrust force is supported by the electromagnet, it is possible to reduce the thrust force acting on the rolling bearing for supporting the main shaft while suppressing an increase in torque without contact. In this case, since the air pressure measuring means for measuring the air pressure of at least one of the compressor and the expansion turbine is provided, the thrust force acting on the main shaft by the air in the compressor and the expansion turbine can be detected. For this reason, by controlling the attraction force of the electromagnet according to the output of the air pressure measuring means, the rolling bearing can be used in an optimum state with respect to the thrust force according to the bearing specifications.
In particular, since the air pressure measuring means is used as the detecting means, the structure of the detecting means is simple and highly reliable.

Therefore, stable high-speed rotation of the main shaft can be obtained while maintaining an appropriate clearance between the impellers, and the long-term durability and life of the rolling bearing can be improved. Since the long-term durability of the rolling bearing for supporting the main shaft is improved, the reliability of the entire air cycle refrigeration cooling turbine unit and, as a whole, the air cycle refrigeration cooling system is improved. As described above, stable high-speed rotation, long-term durability, and reliability of the main shaft bearing of the turbine unit, which is a bottleneck of the air cycle refrigeration cooling system, are improved, and thus the air cycle refrigeration cooling system can be put to practical use.
Further, the overall operating status of the air cycle refrigeration cooling system affects the air pressure in the compressor and the expansion turbine, but the air pressure measuring means measures the air pressure of at least one of the compressor and the expansion turbine. Besides the control of the electromagnet, it can also be used for monitoring the operating status of the air cycle refrigeration cooling system.

In the air cycle refrigeration cooling turbine unit of the present invention, the compressor impeller of the compressor and the turbine impeller of the expansion turbine and the motor rotor are attached to a common main shaft, and the main shaft is rotated by a magnetic force from a motor stator opposed to the motor rotor. Thus, the compressor impeller may be driven.
When the main shaft is driven by providing a motor, it is not necessary to provide pre-compression means such as a blower before the compressor.

The air pressure measuring means detects at least one of an output side pressure of the expansion turbine, a back pressure of the turbine impeller, an input side pressure of the compressor, and a back pressure of the compressor impeller.
When the air pressure of any of the above parts is detected, the thrust force acting on the main shaft can be detected.

A plurality of air pressure measuring means for measuring all of the output side pressure of the expansion turbine, the back pressure of the turbine impeller, the input side pressure of the compressor, and the back pressure of the compressor impeller may be provided as the air pressure measuring means. good.
By measuring these four air pressures, the thrust force acting on the main shaft can be detected with high accuracy.

When air pressure measuring means for detecting air pressure at a plurality of locations among the output side pressure of the expansion turbine, the back pressure of the turbine impeller, the input side pressure of the compressor, and the back pressure of the compressor impeller is provided, Thrust force estimation calculating means for calculating an estimated value of thrust force acting on the main shaft from the output of the air pressure measuring means may be provided.
By calculating the estimated value of the thrust force acting on the main shaft from the outputs of the plurality of air pressure measuring means, a sensor output suitable for controlling the thrust force can be obtained with high accuracy.

In the present invention, a temperature sensor may be provided in the vicinity of the air pressure measuring means, and a temperature correcting means for correcting the output of the air pressure measuring means by the output of the temperature sensor may be provided.
Since the temperature of each part of the turbine unit fluctuates, accurate detection can be performed by providing a temperature sensor and correcting the measured value of the air pressure measuring means. Since the temperature sensor is provided in the vicinity of the air pressure measuring means, more accurate temperature correction can be performed.

In this invention, you may provide the controller which controls the bearing force by the said electromagnet according to the output of the said air pressure measurement means.
By controlling the bearing force by the electromagnet, the rolling bearing that rotates the main shaft can be used in an optimum state against the thrust force, and the rolling bearing has higher speed stability, improved long-term durability, and longer life. As a result, the stability of the system is further improved.

The controller may be attached to the spindle housing.
By attaching the controller to the spindle housing, the connection between the electromagnet and the controller can be simplified and the system can be made compact.

In the present invention, a DC power supply may be used to supply power to the controller.
By supplying DC power, the power circuit in the controller can be made compact.

The air cycle refrigeration cooling turbine unit of the present invention is an air cycle refrigeration cooling turbine unit having a compressor and an expansion turbine, wherein the compressor impeller of the compressor and the turbine impeller of the expansion turbine are respectively provided at both ends of the main shaft. The compressor impeller is driven by the power generated by the turbine impeller, the main shaft is supported by a rolling bearing in the radial direction, the thrust force applied to the main shaft is supported by an electromagnet, the compressor and Since the air pressure measuring means for measuring the air pressure of at least one of the expansion turbines is provided, the structure of the means for detecting the thrust force acting on the main shaft is simple and reliable, and stable high speed rotation is possible while maintaining a minute gap of the impeller. Improved and long-term durability of bearings that support the main shaft Service life, Hakare reliability improvement, also it is possible to monitor the operating status of the air cycle refrigeration cooling system.
In the turbine unit for air cycle refrigeration cooling according to the present invention, the compressor impeller of the compressor and the turbine impeller of the expansion turbine and the motor rotor are attached to a common main shaft, and the main shaft is rotated by the magnetic force from the motor stator opposed to the motor rotor. Thus, even when the compressor impeller is driven, the main shaft is supported by a rolling bearing in a radial direction, the thrust force applied to the main shaft is supported by an electromagnet, and at least one of the compressor and the expansion turbine is supported. By providing air pressure measurement means for measuring air pressure, the structure of the thrust force detection means acting on the main shaft is simple and reliable, and stable high-speed rotation is obtained while maintaining a minute gap of the impeller, and the main shaft is Improved long-term durability, longer life, and reliability of supporting bearings Improved Hakare, also can be monitored the operation status of the air cycle refrigeration cooling system.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the overall configuration of an air cycle refrigeration cooling system. This air cycle refrigeration cooling system is a system that directly cools air in a space to be cooled 10 such as a freezer as a refrigerant, and an air circulation path from an air intake port 1a to a discharge port 1b respectively opened in the space to be cooled 10 1 In this air circulation path 1, pre-compression means 2, first heat exchanger 3, dehumidifier 4, compressor 6 of air cycle refrigeration cooling turbine unit 5, second heat exchanger 8, intermediate heat exchanger 9, And the expansion turbine 7 of the said turbine unit 5 is provided in order. The intermediate heat exchanger 9 exchanges heat between the inflow air near the intake port 1a in the same air circulation path 1 and the air that has been heated by the subsequent compression and cooled. Air in the vicinity of 1 a passes through the coil 9 a of the heat exchanger 9.

  The pre-compression means 2 comprises a blower or the like and is driven by a motor 2a. The first heat exchanger 3 and the second heat exchanger 8 have heat exchangers 3a and 8a for circulating a cooling medium, respectively, and a cooling medium such as water and an air circulation path in the heat exchangers 3a and 8a. Heat exchange with 1 air. Each of the heat exchangers 3 a and 8 a is connected to the cooling tower 11 by piping, and the cooling medium whose temperature is increased by heat exchange is cooled by the cooling tower 11.

  This air cycle refrigeration cooling system is a system that keeps the space to be cooled 10 at about 0 ° C. to −60 ° C., and as an example from the space to be cooled 10 to the intake port 1a of the air circulation path 1 at about −30 ° C. and 1 atm. Air flows in. Note that the numerical values of temperature and atmospheric pressure shown below are examples that serve as a guide. The air that has flowed into the intake port 1a is used by the intermediate heat exchanger 9 to cool the downstream air in the air circulation path 1 and is heated to 30 ° C. The heated air remains at 1 atm, but is compressed to 1.4 atm by the pre-compression means 2, and the temperature is raised to 65 ° C. by the compression. Since the 1st heat exchanger 3 should just cool the 65 degreeC air which raised temperature, even if it is cold water about normal temperature, it can cool efficiently and it cools to 40 degreeC. The dehumidifier 4 prevents the moisture in the air in the air circulation path 1 from freezing due to cooling below the freezing point in the subsequent stage and causing clogging of the air circulation path 1 and galling of the expansion turbine 7. Dehumidify the air.

The air at 40 ° C. and 1.4 atm after dehumidification is compressed to 1.8 atm by the compressor 6 of the turbine unit 5, and the second heat exchanger 8 is heated to about 70 ° C. by this compression. To 40 ° C. The 40 ° C. air is cooled to −20 ° C. by the −30 ° C. air in the intermediate heat exchanger 9. The atmospheric pressure is maintained at 1.8 atmospheric pressure discharged from the compressor 6.
The air cooled to −20 ° C. by the intermediate heat exchanger 9 is adiabatically expanded by the expansion turbine 7 of the turbine unit 5, cooled to −55 ° C., and discharged from the outlet 1 b to the cooled space 10. This air cycle refrigeration cooling system performs such a refrigeration cycle.

  FIG. 2 shows a specific example of the turbine unit 5 for air cycle refrigeration cooling. The turbine unit 5 includes a compressor 6 and an expansion turbine 7. A compressor impeller 6 a of the compressor 6 and a turbine impeller 7 a of the expansion turbine 7 are respectively attached to both ends of the main shaft 13. Further, the compressor impeller 6a is driven by the power generated in the turbine impeller 7a, and no other drive source is provided.

  As shown in FIG. 5, the compressor impeller 6 a of the compressor 6, the turbine impeller 7 a of the expansion turbine 7, and the motor rotor 92 may be attached to the common main shaft 13, and the main shaft 13 may be driven by the driving force of the motor 90. . The motor 90 includes a stator 91 having a stator coil 91 a and installed in the spindle housing 14, and the motor rotor 92, and is controlled by a motor controller 93. When the motor 90 is provided to drive the main shaft 13, it is not necessary to provide the pre-compression means 2 (FIG. 1) such as a blower before the compressor 6.

In FIG. 2, the compressor 6 has a diffuser 6b facing the compressor impeller 6a with a minute gap d1, and compresses the air sucked in the axial direction from the suction port 6c in the center by the compressor impeller 6a. Then, it is discharged from the outlet (not shown) of the outer peripheral portion as shown by an arrow 6d.
The expansion turbine 7 has a housing 7b that opposes the turbine impeller 7a with a minute gap d2, and aspirates and expands the air sucked from the outer peripheral portion as indicated by an arrow 7c by the turbine impeller 7a. Is discharged in the axial direction from the discharge port 7d.

In the turbine unit 5, the main shaft 13 is supported by a plurality of bearings 15 and 16 in the radial direction, and the thrust force applied to the main shaft 13 is supported by electromagnets 17 (17 ₁ and 17 ₂ ). The turbine unit 5 is provided with pressure sensors 61 to 64 described later as air pressure detecting means for detecting a thrust force acting on the main shaft 13 by the air in the compressor 6 and the expansion turbine 7. A controller 19 is provided for controlling the bearing force of the electromagnet 17 in accordance with the estimated thrust force obtained by calculating the output. The electromagnet 17 is installed in the spindle housing 14 so as to face the both surfaces of a flange-like thrust plate 13a made of a ferromagnetic material provided at the center of the main shaft 13 without contact.

  The bearings 15 and 16 for supporting the main shaft 13 are rolling bearings and have a function of regulating the axial position, and for example, deep groove ball bearings are used. In the case of a deep groove ball bearing, it has a thrust support function in both directions, and has the effect of returning the axial position of the inner and outer rings to the neutral position. These two bearings 15 and 16 are arranged in the vicinity of the compressor impeller 6a and the turbine impeller 7a in the spindle housing 14, respectively.

The main shaft 13 is a stepped shaft having a large-diameter portion 13b at the center and small-diameter portions 13c at both ends. The bearings 15 and 16 on both sides have their inner rings 15a and 16a fitted into the small diameter portion 13c in a press-fit state, and one of the width surfaces engages with a stepped surface between the large diameter portion 13b and the small diameter portion 13c.
The portions of the spindle housing 14 closer to the impellers 6a and 7a than the bearings 15 and 16 on both sides are formed with an inner diameter surface close to the main shaft 13, and non-contact seals 21 and 22 are formed on the inner diameter surface. Yes. The non-contact seals 21 and 22 are labyrinth seals in which a plurality of circumferential grooves are arranged in the axial direction on the inner diameter surface of the spindle housing 14.

  Of the bearings 15 and 16, the bearing 16 on the turbine impeller 7 a side is installed such that its outer ring 16 a is immovable in the axial direction with respect to the spindle housing 14. The bearing 15 on the compressor impeller 6 a side is installed in an inner diameter hole provided in the spindle housing 14 so as to be elastically movable in the axial direction by a spring element 26. The spring element 26 acts to press the bearing 15 against the stepped surface of the main shaft 13 and applies a preload to the bearing 15.

  Each of the pressure sensors 61 to 64 detects the output side pressure of the expansion turbine 7, the back pressure of the turbine impeller 7a, the input side pressure of the compressor 6, and the back pressure of the compressor impeller 6a. These pressure sensors 61 to 64 are installed inside or outside the spindle housing 14, and air pressure introduction paths 61 a to 64 a such as pipes for guiding the air pressure of each detection portion to each pressure sensor 61 to 64 are provided.

The air pressure introduction path 61a of the pressure sensor 61 opens to the discharge port 7d of the expansion turbine 7, and the air pressure introduction path 62a of the pressure sensor 62 opens to the inner surface of the spindle housing 14 facing the back surface of the turbine impeller 7a.
The air pressure introduction path 63a of the pressure sensor 63 opens to the suction port 6c of the compressor 6, and the air pressure introduction path 64a of the pressure sensor 64 opens to the inner surface of the spindle housing 14 facing the back surface of the compressor impeller 6a.
Note that all of the four pressure sensors 61 to 64 are not necessarily provided, and at least one of the pressure sensors 61 to 64 may be provided.

  Temperature sensors 65 to 68 are provided in the vicinity of the pressure sensors 61 to 64, respectively. The outputs of the pressure sensors 61 to 64 and the temperature sensors 65 to 68 are input to the controller 19A.

FIG. 3 is a block diagram of the controller 19A in the turbine unit 5 of FIG. The detection outputs P _{61 to} P _{64 of the} pressure sensors 61 to ₆₄ and the outputs T _{65 to} T ₆₈ of the temperature sensors _{65 to 68} in FIG. 2 are input to the temperature compensation circuits 74A to 74D, and the outputs P of the pressure sensors 61 to 64 are input. _{61 to} P ₆₄ are input to the thrust force estimation calculation circuit 71 after temperature correction. The thrust force estimation calculation circuit 71 compares the estimated output of the thrust force acting on the main shaft 13 with the reference value of the reference value setting means 72 by the comparator 75, and calculates the deviation.
The calculated deviation is processed by the PID compensation circuit 76 by proportional, differential, and integral operations that are appropriately set according to the turbine unit 5.

The output of the PID compensation circuit 76 is input to power circuits 79 and 80 that drive the electromagnets 17 ₁ and 17 ₂ in each direction via diodes 77 and 78. The electromagnets 17 ₁ and 17 ₂ are a pair of electromagnets 17 facing the thrust plate 13a shown in FIG. 2, and only the attractive force acts. Therefore, the direction of current is determined in advance by the diodes 77 and 78, and the two electromagnets 17 are used. ₁ and 17 ₂ are selectively driven.

FIG. 4 shows a turbine unit 5 according to still another embodiment. This structure has a configuration in which a controller 19A is built in the turbine unit 5. With this configuration, the cable between the controller 19A and the electromagnet 17 and the cable between the controller 19A and the sensors 61 to 68 can be shortened, and the connection is simple, which is advantageous in terms of cost, and at the same time, an external sensor. The entire circuit system configuration can be made compact.
In the configuration in which the motor 90 is arranged in the turbine unit 5 as in the example of FIG. 5, since a cable between the motor 90 and its controller 93 is also necessary, the illustration is omitted. The configuration incorporating 19A is further advantageous. In that case, the motor controller 93 is also built in the turbine unit 5.

  The operation of the above configuration will be described. In the air cycle refrigeration cooling system, the turbine unit 5 having this configuration is compressed by the compressor 5 to increase the temperature so that the air serving as a cooling medium can be efficiently heat exchanged by the heat exchangers 8 and 9 (FIG. 1). The air cooled by the heat exchangers 8 and 9 is used by the expansion turbine 7 to be cooled and discharged by adiabatic expansion to a target temperature, for example, a very low temperature of about −30 ° C. to 60 ° C.

In this turbine unit 5, the compressor impeller 6a and the turbine impeller 7a are attached to a common main shaft 13, and the compressor impeller 6a is driven by the power generated in the turbine impeller 7a, so that no power source is required. Cooling can be efficiently performed with a compact configuration.
In order to secure the efficiency of compression and expansion of the turbine unit 5, it is necessary to keep the gaps d1 and d2 between the impellers 6a and 7a and the housings 6b and 7b minute. In the air cycle refrigeration cooling system, ensuring this efficiency is important. On the other hand, since the main shaft 13 is supported by the rolling bearings 15 and 16, the axial position of the main shaft 13 is regulated to some extent by the restriction function of the axial position of the rolling bearing, and the impellers 6a and 7a The minute gaps d1 and d2 between the housings 6b and 7b can be kept constant.

However, a thrust force is applied to the main shaft 13 of the turbine unit 5 by the pressure of air acting on the impellers 6a and 7a. Further, the turbine unit 5 used in the air cooling system rotates at a very high speed of about 80,000 to 100,000 rotations per minute, for example. Therefore, when the thrust force acts on the rolling bearings 15 and 16 that rotatably support the main shaft 13, the long-term durability of the bearings 15 and 16 decreases.
In this embodiment, since the thrust force is supported by the electromagnet 17, the thrust force acting on the rolling bearings 15 and 16 for supporting the main shaft 13 can be reduced while suppressing an increase in torque without contact. In this case, the pressure sensors 61 to 64 for detecting the thrust force acting on the main shaft 13 by the air in the compressor 6 and the expansion turbine 7 and the estimated thrust force calculated from the output of the pressure sensors 61 to 64 are used. The controller 19 for controlling the bearing force by the electromagnet 17 is provided so that the thrust force can be canceled. Therefore, excessive thrust force does not act on the rolling bearings 15 and 16 with respect to the bearing specifications. It can be used in an optimum state against the thrust force.

  Therefore, stable high-speed rotation of the main shaft 13 can be obtained while maintaining appropriate gaps d1 and d2 between the impellers 6a and 7a, and the long-term durability and life of the bearings 15 and 16 can be improved. Since the long-term durability of the bearings 15 and 16 is improved, the reliability of the entire air cooling turbine unit 5 and, as a whole, the air cycle refrigeration cooling system is improved. As described above, stable high-speed rotation, long-term durability, and reliability of the main shaft bearings 15 and 16 of the turbine unit 5 that are the bottleneck of the air cycle refrigeration cooling system are improved. It becomes possible.

  In particular, in this embodiment, since the pressure sensors 61 to 64 are used as the detecting means for the thrust force acting on the main shaft 13, the structure of the detecting means is simple, reliable and inexpensive. In addition, the overall operating status of the air cycle refrigeration cooling system also affects the air pressure in the compressor 6 and the expansion turbine 7 of the turbine unit 5, but since the pressure sensors 61 to 64 for detecting the air pressure are provided, The operating status of the air cycle refrigeration cooling system can also be monitored.

  The bearings 15 and 16 are disposed in the vicinity of the compressor impeller 6a and in the vicinity of the turbine impeller 7a, and the main shaft 13 is supported at both ends, so that more stable high-speed rotation is possible. Further, since the bearings 15 and 16 formed of rolling bearings are preloaded by the spring element 26, the axial position of the main shaft 13 is stabilized, and the minute gaps d1 and d2 of the respective impellers 6a and 7a are more reliably secured. Maintained, and more stable high-speed rotation can be obtained.

  Since non-contact seals 21 and 22 are provided between the main shaft 13 and the spindle housing 14 on the end side of the bearings 15 and 16, air passes through the bearings 15 and 16 and the like with the compressor 6. Leakage between the expansion turbines 7 is prevented. Since there is a large pressure difference between the inside of the compressor 6 and the inside of the expansion turbine 7, the inside of each bearing 15, 16 and the surface on which the inner and outer rings 15 a, 16 a of each bearing 15, 16 are fitted to the main shaft 13 and the spindle housing 14. Air leaks are about to occur. Such air leakage causes the efficiency of the compressor 6 and the expansion turbine 7 to decrease, and if the lubricant in the bearings is dried by the air passing through the bearings 15 and 16 or if dust is present in the air, the bearings. There is a possibility that the inside of the 15 and 16 may be soiled to reduce the durability. Such a decrease in efficiency and the fouling of the bearings 15 and 16 are prevented by the non-contact seals 21 and 22.

1 is a system diagram of an air cycle refrigeration cooling system using an air cycle refrigeration cooling turbine unit according to an embodiment of the present invention. It is sectional drawing of the turbine unit for air cycle refrigeration cooling which concerns on one Embodiment of this invention. It is a block diagram showing an example of a controller used for the turbine unit. It is sectional drawing of the turbine unit for air cycle refrigeration cooling which concerns on other embodiment. It is sectional drawing of the turbine unit for air cycle refrigeration cooling which concerns on other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Air circulation path 1a ... Intake port 1b ... Exhaust port 2 ... Precompression means 3 ... 1st heat exchanger 5 ... Air cycle refrigeration cooling turbine unit 6 ... Compressor 6a ... Compressor impeller 7 ... Expansion turbine 7a ... Turbine blade Car 8 ... Second heat exchanger 9 ... Intermediate heat exchanger 10 ... Cooled space 13 ... Main shaft 13a ... Thrust plate 14 ... Spindle housing 15, 16 ... Bearing 17 ... Electromagnet 19A ... Controllers 21, 22 ... Non-contact seal 26 ... Spring elements 61 to 64 ... Pressure sensor (air pressure measuring means)
65-68 ... temperature sensor 90 ... motor 93 ... motor controller

Claims (8)

  An air cycle refrigeration cooling turbine unit having a compressor and an expansion turbine, wherein the compressor impeller of the compressor and the turbine impeller of the expansion turbine are respectively attached to both ends of the main shaft, and the compressor is driven by power generated by the turbine impeller. An air wheel that drives an impeller, supports the main shaft with a rolling bearing in a radial direction, supports the thrust force applied to the main shaft with an electromagnet, and measures the air pressure of at least one of the compressor and the expansion turbine. A turbine unit for air cycle refrigeration cooling, comprising a measuring means. An air cycle refrigeration cooling turbine unit having a compressor and an expansion turbine,
The turbine unit is configured such that the compressor impeller of the compressor and the turbine impeller of the expansion turbine and the motor rotor are attached to a common main shaft, and the main shaft is rotated by a magnetic force from a motor stator opposed to the motor rotor. Air pressure measuring means for measuring the air pressure of at least one of the compressor and the expansion turbine by supporting the main shaft with a rolling bearing in a radial direction, supporting the thrust force applied to the main shaft with an electromagnet, and An air cycle refrigeration cooling turbine unit provided.   3. The air pressure measuring means according to claim 1, wherein the air pressure measuring means detects at least one of an output side pressure of the expansion turbine, a back pressure of the turbine impeller, an input side pressure of the compressor, and a back pressure of the compressor impeller. Turbine unit for air cycle refrigeration cooling.   3. A plurality of air pressure measuring means for measuring all of an output side pressure of the expansion turbine, a back pressure of the turbine impeller, an input side pressure of the compressor, and a back pressure of the compressor impeller according to claim 1 or 2. Air cycle refrigeration cooling turbine unit.   5. The method according to claim 1, further comprising a plurality of air pressure detecting means, and a thrust force estimating calculating means for calculating an estimated value of a thrust force applied to the main shaft from outputs of the plurality of air pressure measuring means. Air cycle refrigeration cooling turbine unit.   6. The air cycle refrigeration according to claim 1, wherein a temperature sensor is provided in the vicinity of the air pressure measuring means, and a temperature correcting means for correcting the output of the air pressure measuring means by the output of the temperature sensor is provided. Turbine unit for cooling.   6. The turbine unit for air cycle refrigeration cooling according to claim 5, wherein a controller for controlling a bearing force by the electromagnet according to an estimated value of a thrust force applied to the main shaft is provided.   8. The controller according to claim 1, wherein a controller for controlling a bearing force by the electromagnet according to an output of the air pressure measuring means is provided, and the controller is for air cycle refrigeration cooling attached to a spindle housing. Turbine unit.

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