JP2009050065A - Motor-integrated magnetic bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor-integrated magnetic bearing device wherein it is possible to enhance the long-term durability of a roller bearing against thrust load, cope with size reduction and the enhancement of rotation speed, and efficiently cool a motor without degrading motor efficiency through simple construction. <P>SOLUTION: The motor-integrated magnetic bearing device includes the roller bearing and a magnetic bearing that support a spindle 13 provided with a compressor impeller and a turbine impeller. The rotor 28a of a motor 28 is provided on the spindle 13 and a motor stator 28b having a motor coil 28ba is installed opposite to the motor rotor 28a in a spindle housing 14. A motor cooling flow path 41 penetrating the motor 28 placement area in the spindle housing 14 is provided. A current plate 43 that is positioned in the motor cooling flow path 41 and changes the direction of a coolant flow is attached to the spindle housing 14. The current plate 43 changes the direction of the coolant flow so that the direction is identical with the direction of rotation of the motor rotor 28a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic bearing device used in an air cycle refrigeration cooling turbine unit or the like, and in particular, a rolling bearing and a magnetic bearing are used together so that the magnetic bearing supports one or both of an axial load and a bearing preload. The present invention relates to a motor-integrated magnetic bearing device.

  Since the air cycle refrigeration cooling system uses air as a refrigerant, energy efficiency is insufficient as compared with the case of using chlorofluorocarbon or ammonia gas, but it is preferable in terms of environmental protection. In addition, in facilities where refrigerant air can be directly blown into, such as a refrigerated warehouse, the total cost may be reduced by omitting the internal fan and defrost, etc. In such applications, the air cycle refrigeration cooling system Has been proposed (for example, Patent Document 1).

Further, it is known that the theoretical efficiency of air cooling is equal to or higher than that of Freon or ammonia gas in a deep coal region of -30 ° C to -60 ° C. 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).

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

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.
Further, a thrust force acts on the main shaft by 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 cycle refrigeration cooling system is 80,000 to 100,000 rotations per minute, which is very high compared with 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 such a problem of long-term durability of the bearing is solved, it is difficult to put the air cycle refrigeration cooling turbine unit into practical use. However, the technique disclosed in Patent Document 1 has not yet been solved for the deterioration of the long-term durability of the bearing against the load of the thrust load under the 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. Therefore, 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 diffuser. In the case of a magnetic bearing, there is also a problem of contact when the power is stopped.

Accordingly, a motor-integrated magnetic bearing device has been proposed in which a rolling bearing and a thrust-supporting magnetic bearing are used together to support the main shaft, and the thrust plate of the magnetic bearing is used as a motor rotor (for example, Japanese Patent Application No. 2005-356035).
According to this, since the thrust force applied to the main shaft is supported by the magnetic bearing, it is possible to reduce the thrust force acting on the rolling bearing while suppressing an increase in torque without contact. As a result, the minute gaps between the respective impellers and the housing can be kept constant, and the long-term durability of the rolling bearing against the thrust load can be improved. Moreover, a compact configuration can be achieved by integrating the magnetic bearing and the motor rotor.

  However, the motor cooling performance was not enough. In the motor-integrated magnetic bearing device, a magnetic bearing and a motor are provided, and heat generated by a coil or the like in the magnetic bearing and heat generated by the motor are generated, so that it is difficult to obtain a sufficient cooling effect. In particular, if the thrust plate of the main shaft is used for mounting the electromagnet target of the magnetic bearing and the permanent magnet for the motor rotor, it is excellent in terms of compactness, but the amount of heat generated by the motor becomes very large. Insufficient cooling of the motor not only reduces the motor efficiency and limits the rotation speed, but also relates to safety, so effective cooling measures are required. In addition, providing the means for circulating the coolant complicates the configuration.

  In the motor-integrated magnetic bearing device having the above-described configuration, as shown in FIG. 6, a motor cooling passage 71 that penetrates the placement portion of the motor 68 in the housing 54 is provided, and the motor cooling passage is provided in the refrigerant passage of the refrigeration cycle apparatus. It was considered that the refrigerant is used for cooling the motor 68 by interposing the flow path 71. In the figure, a motor 68 is configured to face a motor rotor 68a in which a permanent magnet (not shown) is disposed on one surface of a thrust plate 53a provided integrally with a main shaft 53, and to face the motor rotor 68a in the axial direction. And a motor stator 68b provided in the housing 54.

  In the case of such a configuration, as indicated by an arrow in FIG. 6, if the refrigerant flows in a direction perpendicular to the rotation axis (main axis) 53 of the motor 68, the refrigerant flows across the thrust plate 53 a. However, in a state where the main shaft 53 is rotating, the rotation direction indicated by the arrow R coincides with the direction in which the refrigerant flows in the half circumference of the end surface and the outer diameter surface of the thrust plate 53a, and the refrigerant helps the motor 68 to rotate. However, since the flow direction of the refrigerant is opposite to the rotation direction in the other half circumference of the end face and the outer diameter surface of the thrust plate 53a, the refrigerant acts in a direction that prevents the motor 68 from rotating. It becomes a load. For this reason, the problem that motor efficiency will fall arises.

An object of the present invention is to improve the long-term durability of a rolling bearing against a thrust load, to be able to cope with downsizing and high-speed rotation, and to efficiently cool a motor without reducing motor efficiency with a simple configuration. A motor-integrated magnetic bearing device is provided.
Another aspect of the present invention is to enable forced feeding of the refrigerant to the motor without requiring a dedicated blower for cooling the motor.

  A motor-integrated magnetic bearing device of the present invention includes a rolling bearing and a magnetic bearing that support a main shaft provided with a compressor impeller and a turbine impeller, and a motor that rotationally drives the main shaft, and the rolling bearing is a radial load. The magnetic bearing supports one or both of an axial load and a bearing preload, and the electromagnet constituting the magnetic bearing is in contact with a flange-shaped thrust plate made of a ferromagnetic material provided on the main shaft. A motor-integrated magnetic bearing device that is mounted on a spindle housing so as to be opposed to each other and the rotor of the motor is installed on the spindle housing, the motor cooling flow passing through the motor arrangement portion in the spindle housing A compressor having the compressor impeller, and an expansion turbine having the turbine impeller The motor cooling flow path is interposed in the refrigerant flow path of the refrigeration cycle apparatus in which the bin is interposed, and a rectifying plate that is located in the motor cooling flow path and changes the flow direction of the refrigerant is attached to the spindle housing, and the rectification is performed. The plate is characterized in that the direction in which the changed refrigerant flows is the same as the direction of rotation of the motor rotor.

According to this configuration, the rolling bearing and the magnetic bearing are used together, the rolling bearing supports the radial load, and the magnetic bearing supports one or both of the axial load and the bearing preload. Good support can be achieved, long-term durability of the rolling bearing can be ensured, and damage when the power supply is stopped in the case of supporting only the magnetic bearing can be avoided.
In addition, a motor cooling flow path that penetrates the arrangement portion of the motor in the spindle housing is provided, and the refrigerant flow path of the refrigeration cycle apparatus in which the compressor having the compressor impeller and the expansion turbine having the turbine impeller are interposed. Since the motor cooling flow path is interposed, the necessary motor cooling can be performed with a simple configuration having only the motor cooling flow path, and the refrigerant supply to the motor is not required without using a dedicated refrigerant supply source such as blowers. Forced feeding can be performed.
In particular, a rectifying plate that is located in the motor cooling flow path and changes the direction in which the refrigerant flows is attached to the spindle housing, and the rectifying plate has a direction in which the changed refrigerant flows in the same direction as the rotation direction of the motor rotor. Therefore, the flow of the refrigerant acts to assist the rotation of the motor, and the motor load is reduced. As a result, the motor can be efficiently cooled with a simple configuration without reducing the motor efficiency.

  In this invention, the front-end | tip of the said baffle plate may be arrange | positioned in the vicinity of the outer diameter surface of the said motor rotor. When the tip of the rectifying plate is in the vicinity of the outer diameter surface of the motor rotor, the action of assisting the rotation of the motor by the flow of the refrigerant is made more effective by making the direction of the refrigerant flowing by the rectifying plate the same as the rotation direction of the motor rotor. To be demonstrated.

In this invention, the refrigerant flow path of the refrigeration cycle apparatus includes a heat exchanger that cools the refrigerant discharged from the compressor, and the motor cooling flow is provided in a portion of the refrigerant flow path that is subsequent to the heat exchanger. A road may be interposed.
In this configuration, since the refrigerant discharged from the compressor and cooled by the heat exchanger is supplied to the motor through the motor cooling flow path, efficient motor cooling can be performed.

  In the present invention, the motor is an axial gap type motor, and the rotor of the motor is composed of the thrust plate and a plurality of permanent magnets provided on the thrust plate at an equal pitch in the circumferential direction. It may be. In the case of an axial gap type motor, the main shaft can be configured to be short, the natural frequency of the main shaft can be increased accordingly, and the main shaft can be rotated at high speed without causing resonance problems. On the other hand, it is difficult to perform efficient cooling of the motor. However, the necessary cooling of the motor can be performed by providing the motor cooling flow path as described above.

In the present invention, the two thrust plates are provided opposite to the main shaft, the motor coil is disposed between the two thrust plates, the permanent magnets are provided on the two thrust plates, and the two thrust plates are provided. The electromagnets of the magnetic bearings are arranged so as to face the surfaces of the plates opposite to each other, and the motor cooling channel is located in the two thrust plates and the motor coil. Also good.
In the case of this configuration, the refrigerant flowing into the motor cooling flow path flows through the two thrust plates that constitute the motor rotor and the arrangement portion of the motor coil that constitutes the motor stator. Cooling can be performed.

In this invention, the refrigeration cycle device performs air conditioning or refrigeration by sequentially performing compression by the compressor, cooling by another heat exchanger, and adiabatic expansion by the expansion turbine with respect to the inflow air serving as the refrigerant. It may be a cycle refrigeration cooling system.
When the refrigeration cycle apparatus is such an air cycle refrigeration cooling system, in the compression / expansion turbine system, stable high-speed rotation of the main shaft can be obtained while maintaining an appropriate gap between the impellers, and the long-term durability of the bearing can be improved. Since the improvement and the improvement of the service life can be obtained, the reliability is improved as a whole of the compression / expansion turbine system and also as a whole of the air cycle refrigeration cooling system. In addition, stable high-speed rotation, long-term durability, and reliability of the main shaft bearing of the compression / expansion turbine system, which is the bottleneck of the air cycle refrigeration cooling system, improve the practical use of the air cycle refrigeration cooling system. .

A motor-integrated magnetic bearing device of the present invention includes a rolling bearing and a magnetic bearing that support a main shaft provided with a compressor impeller and a turbine impeller, and a motor that rotationally drives the main shaft, and the rolling bearing is a radial load. The magnetic bearing supports one or both of an axial load and a bearing preload, and the electromagnet constituting the magnetic bearing is in contact with a flange-shaped thrust plate made of a ferromagnetic material provided on the main shaft. A motor-integrated magnetic bearing device that is mounted on a spindle housing so as to be opposed to each other and the rotor of the motor is installed on the spindle housing, the motor cooling flow passing through the motor arrangement portion in the spindle housing A compressor having the compressor impeller, and an expansion turbine having the turbine impeller The motor cooling flow path is interposed in the refrigerant flow path of the refrigeration cycle apparatus in which the bin is interposed, and a rectifying plate that is located in the motor cooling flow path and changes the flow direction of the refrigerant is attached to the spindle housing, and the rectification is performed. Since the direction of the flow of the refrigerant in the plate is the same as the direction of rotation of the motor rotor, the motor can be efficiently cooled with a simple configuration without reducing the motor efficiency.
In particular, the refrigerant can be forcibly fed without requiring a dedicated blower for supplying the refrigerant, and efficient motor cooling can be performed with a simple configuration.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a cross-sectional view of a turbine unit 5 incorporating a motor-integrated magnetic bearing device of this embodiment. The turbine unit 5 constitutes a compression / expansion turbine system, and includes a compressor 6 and an expansion turbine 7. The compressor impeller 6 a of the compressor 6 and the turbine impeller 7 a of the expansion turbine 7 are fitted to both ends of the main shaft 13. Fixed together. The material of the main shaft 13 is low carbon steel with good magnetic properties.

In FIG. 1, a compressor 6 has a compressor housing 6b facing the compressor impeller 6a via a gap d1, and compresses the air sucked in the axial direction from the suction port 6c in the center with the compressor impeller 6a. As shown by the arrow 6d, it discharges | emits from the exit (not shown) of an outer peripheral part.
The expansion turbine 7 has a turbine housing 7b that is opposed to the turbine impeller 7a via a minute gap d2, and the air sucked from the outer peripheral portion as indicated by an arrow 7c is adiabatically expanded by the turbine impeller 7a, It discharges in the axial direction from the discharge port 7d of the part.

The motor-integrated magnetic bearing device in the turbine unit 5 supports the main shaft 13 with a plurality of rolling bearings 15 and 16 in the radial direction, and either or both of an axial load and a bearing preload applied to the main shaft 13 are respectively provided. An axial gap motor 28 is provided which is supported by the electromagnet 17 and the permanent magnet 17A serving as magnetic bearings and which drives the main shaft 13 to rotate. The turbine unit 5 includes a sensor 18 that detects a thrust force acting on the main shaft 13, a magnetic bearing controller 19 that controls the supporting force of the electromagnet 17 in accordance with the output of the sensor 18, and the electromagnet 17. A motor controller 29 for controlling the motor 28;
Two flange-shaped thrust plates 13 a and 13 b made of a ferromagnetic material are provided in the axial direction intermediate portion of the main shaft 13 so as to be perpendicular to the main shaft 13 and coaxial with each other in the axial direction. The electromagnet 17 which is a component of one of the magnetic bearings is configured such that, of the two thrust plates 13a and 13b, one surface of the thrust plate 13a located near the compressor 6 facing the compressor 6 is used as a magnet target. It is installed in the spindle housing 14 so as to face each other by contact. The permanent magnet 17A, which is a component of the other magnetic bearing, has a spindle housing that faces one side of the thrust plate 13b positioned near the expansion turbine 7 facing the expansion turbine 7 in a non-contact manner, with the one side facing the expansion turbine 7 being a magnet target. 14 is installed. Although the permanent magnet 17A is used for one of the magnetic bearings here, the permanent magnet 17A may be replaced with the electromagnet 17.

  The motor 28 includes a motor rotor 28a provided on the main shaft 13 and a motor stator 28b facing the motor rotor 28a in the axial direction. Specifically, the motor rotor 28a constituting one part of the motor 28 is circumferentially arranged on one side of the main shaft 13 opposite to the side where the electromagnet 17 and the permanent magnet 17A of the thrust plates 13a and 13b face each other. A pair of left and right ones is formed by arranging permanent magnets 28aa arranged at equal pitches. Thus, the permanent magnets 28aa opposed to each other in the axial direction are set so that their magnetic poles are different from each other. Since the main shaft 13 is made of low carbon steel having good magnetic properties, the thrust plates 13a and 13b provided so as to be integrated with the main shaft 13 are also used as the back yoke and the magnet target of the permanent magnet 28aa. it can.

  The motor stator 28b, which is another part of the motor 28, is arranged in a state where there is no core so as to face each surface of both the motor rotors 28a in a non-contact manner at a central position in the axial direction between the pair of left and right motor rotors 28a. The motor coil 28ba is covered and held by a ring-shaped partition wall 42 concentric with the main shaft 13, and is installed in the spindle housing 14 via the partition wall 42.

  The motor 28 rotates the main shaft 13 by Lorentz force acting between the motor rotor 28a and the motor stator 28b. Thus, since this axial gap type motor 28 is a coreless motor, the negative rigidity due to the magnetic coupling between the motor rotor 28a and the motor stator 28b is zero.

  As a cooling means for the motor 28, a motor cooling channel 41 that penetrates the arrangement portion of the motor 28 is provided in the spindle housing 14. The motor cooling passage 41 is provided in the refrigerant passage 1 of the refrigeration cycle apparatus 50 (described later) in FIG. 5 in which the compressor 6 having the compressor impeller 6a and the expansion turbine 7 having the turbine impeller 7a are interposed. Intervene. Further, the spindle housing 14 is provided with a rectifying plate 43 that is located in the motor cooling flow path 41 and changes the flow direction of the refrigerant. The rectifying plate 43 is configured so that the direction of flow of the refrigerant after the change is the same as the direction of rotation of the motor rotor 28a (indicated by an arrow R in the same figure) as indicated by an arrow in FIG. The tip 43a of the rectifying plate 43 is disposed in the vicinity of the outer diameter surface of the motor rotor 28a.

  The bearings 15 and 16 that support the main shaft 13 are rolling bearings and have a function of restricting the position in the axial direction. For example, a deep groove ball bearing or an angular ball bearing is 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 rolling 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 13c at an intermediate portion and small-diameter portions 13d at both ends. The bearings 15 and 16 on both sides have their inner rings 15a and 16a fitted into the small diameter portion 13d in a press-fit state, and one of the width surfaces engages with a stepped surface between the large diameter portion 13c and the small diameter portion 13d. Seals 21 and 22 for sealing a gap with the main shaft 13 are provided at portions of the spindle housing 14 that are closer to the impellers 6a and 7a than the bearings 15 and 16 on both sides.

  The sensor 18 is provided on the stationary side in the vicinity of the bearing 16 on the turbine impeller 7 a side, that is, on the spindle housing 14 side, and also serves as a bearing housing that supports the outer ring 16 b of the bearing 16. The sensor 18 is fitted to the spindle housing 14 so as to be movable in the axial direction. A preload in the axial direction is applied to the sensor 18 by a sensor preload spring 25.

  The preload by the sensor preload spring 25 is for the sensor 18 that detects the thrust force by the pressing force to detect any movement of the main shaft 13 in the axial direction. The magnitude is greater than the average thrust force acting on the main shaft 13 in the operating state.

  The bearing 15 on the non-arrangement side of the sensor 18 is installed so as to be movable in the axial direction with respect to the spindle housing 14 and is elastically supported by a bearing preload spring 26. In this example, the outer ring 15 b of the bearing 15 is fitted to the inner diameter surface of the spindle housing 14 via the bearing housing 27 so as to be movable in the axial direction, and the bearing preload spring 26 is provided between the bearing housing 27 and the spindle housing 14. Is intervening. The bearing preload spring 26 biases the outer ring 15 b so as to face the step surface of the main shaft 13 with which the width surface of the inner ring 15 a is engaged, and applies a preload to the bearing 15. The bearing preload spring 26 has a smaller spring constant than the sensor preload spring 25.

The dynamic model of the motor-integrated magnetic bearing device in the turbine unit 5 can be constituted by a simple spring system. That is, the spring system includes a composite spring formed by the bearings 15 and 16 and a support system for these bearings (a sensor preload spring 25, a bearing preload spring 26, a bearing housing 27, and the like), and a motor unit (an electromagnet 17 and a permanent magnet). 17A and the composite spring formed by the motor 28) are arranged in parallel. In this spring system, the composite spring formed by the bearings 15 and 16 and the support system of these bearings has rigidity acting in proportion to the amount of displacement in the direction opposite to the displaced direction, while the electromagnet 17 and The composite spring formed by the permanent magnet 17A and the motor 28 has a negative stiffness that acts in proportion to the amount of displacement in the displaced direction.
For this reason, the magnitude relationship between the stiffnesses of the two composite springs described above is
If the stiffness value of the composite spring by the bearing etc. <the negative stiffness value of the composite spring by the electromagnet / motor ... (1), the phase of the mechanical system is delayed by 180 ° and the system becomes unstable, so the electromagnet 17 is controlled. In the magnetic bearing controller 19, the phase compensation circuit needs to be added in advance, and the configuration of the controller 19 becomes complicated.

Therefore, in the motor-integrated magnetic bearing device of this embodiment, the above-described rigidity relationship of the two composite springs is expressed as follows:
Rigidity value of the combined spring by the bearing or the like> Negative rigidity value of the combined spring by the electromagnet / motor (2). In particular, in this motor-integrated magnetic bearing device, since the axial gap type motor 28 is a coreless motor as described above, the negative rigidity value acting on the motor 28 can be made zero, and the motor 28 is high. Even in the state where the load operation is performed and an excessive axial load is applied, the magnitude relationship of the above equation (2) can be maintained.
As a result, since the phase of the mechanical system can be prevented from being delayed by 180 ° in the control band, the controlled object of the magnetic bearing controller 19 can be stabilized even when the motor 28 is operated at a high load and an excessive axial load is applied. The circuit configuration of the controller 19 can be configured as a simple one using proportional or proportional integration as shown in FIG.

  In the magnetic bearing controller 19 shown in the block diagram of FIG. 3, the detection outputs P1 and P2 of the sensor 18 are added and subtracted by the sensor output calculation circuit 30 and the calculation result is compared with the reference value of the reference value setting means 32 by the comparator 31. Then, the deviation is calculated, and the calculated deviation is subjected to proportional integration (or proportional) processing appropriately set according to the turbine unit 5 by the PI compensation circuit (or P compensation circuit) 33, whereby the control signal of the electromagnet 17 is obtained. Is calculated. The output of the PI compensation circuit (or P compensation circuit) 33 is input to a power circuit 34 that drives the electromagnet 17.

  In the motor controller 29 of FIG. 4 also shown in the block diagram, the phase adjustment circuit 38 adjusts the phase of the motor drive current using the rotation angle of the motor rotor 28a as a feedback signal based on the rotation synchronization command signal. Constant rotation control is performed by supplying a corresponding motor drive current from the motor drive circuit 39 to the motor stator 28b. The rotation synchronization command signal is calculated according to the output of a rotation angle detection sensor (not shown) provided in the motor rotor 28a.

The turbine unit 5 having this configuration is used in, for example, an air cycle refrigeration cooling system shown as a refrigeration cycle apparatus 50 in FIG.
In such an example of use, the turbine unit 5 includes a compressor impeller 6a and a turbine impeller 7a fitted on the main shaft 13 common to the thrust plates 13a and 13b and the motor rotor 28a. The compressor impeller 6a is driven by either one or both of the power generated in the vehicle 7a. For this reason, 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.

  In order to ensure 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. For example, when this turbine unit 5 is applied to an air cycle refrigeration cooling system, ensuring this efficiency is important. On the other hand, since the main shaft 13 is supported by rolling type bearings 15 and 16, the axial direction position of the main shaft 13 is regulated to some extent by the restriction function of the axial direction position of the rolling bearing, and each impeller 6a, 7a and The 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 air pressure 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 and the permanent magnet 17A, the thrust force acting on the rolling bearings 15 and 16 for supporting the main shaft 13 is reduced while suppressing an increase in torque without contact. be able to. In this case, since the sensor 18 for detecting the thrust force acting on the main shaft 13 and the magnetic bearing controller 19 for controlling the supporting force by the electromagnet 17 according to the output of the sensor 18 are provided, the rolling bearings 15 and 16 are provided. Can be used in an optimum state against the thrust force according to the bearing specifications.
In particular, one electromagnet 17 and one permanent magnet 17A are arranged on the axially outer side of two thrust plates 13a and 13b provided on the main shaft 13 side by side in the axial direction to constitute a magnetic bearing unit, and both the thrust plates By arranging the axial gap type motor 28 at a position sandwiched between 13a and 13b and configuring the motor unit, the magnetic bearing unit and the motor unit have a compact integrated structure, so that the shaft length of the main shaft 53 can be shortened. Accordingly, the natural frequency of the main shaft 13 is increased, and the main shaft 13 can be rotated at high speed.

  Further, according to this configuration, as a cooling means for the motor 28, the motor cooling channel 41 penetrating the arrangement portion of the motor 28 in the spindle housing 14 is provided, and the compressor 6 having the compressor impeller 6a and the turbine impeller 7a are provided. Since the motor cooling flow path 41 is interposed in the refrigerant flow path 1 of the refrigeration cycle apparatus 50 (FIG. 5) in which the expansion turbine 7 is included, a simple configuration in which the motor cooling flow path 41 is provided is necessary. Motor cooling can be performed. In this case, since the cooling medium (air) flowing through the refrigerant flow path 1 of the refrigeration cycle apparatus 50 is used as the refrigerant flowing through the motor cooling flow path 41, a dedicated refrigerant supply source such as a blower is not required. The refrigerant can be forcedly circulated, and the motor can be efficiently cooled with a simple configuration.

  In particular, a rectifying plate 43 that changes the direction of refrigerant flow is provided in the motor cooling flow path 41, and the changed refrigerant flow direction is the same as the rotation direction R of the motor rotor 28b as shown in FIG. The refrigerant flow acts to assist the rotation of the motor 28. Thereby, the motor load can be reduced and the motor 28 can be efficiently cooled while improving the motor efficiency. In this embodiment, since the front end 43a of the rectifying plate 43 is in the vicinity of the outer diameter surface of the motor rotor 28b, the refrigerant flow direction is set to the same direction as the rotation direction of the motor rotor 28b by the rectifying plate 43. The effect of helping is demonstrated more effectively.

  Since the motor 28 is an axial gap motor, the main shaft 13 can be configured to be short, and the main shaft 13 can be rotated at high speed without causing a resonance problem. However, it is difficult to efficiently cool the motor 28. However, as described above, the refrigerant flowing in the refrigerant flow path 1 of the refrigeration cycle apparatus 50 in which the compressor 6 and the expansion turbine 7 of the turbine unit 5 in which the motor-integrated magnetic bearing device is incorporated is used as the motor in the spindle housing 14. Since it is introduced into the 28 arrangement portions, an excellent cooling effect by forced circulation of the refrigerant can be obtained with a simple configuration.

  The motor cooling channel 41 is installed so that the two thrust plates 13a and 13b and the motor coil 28 are located inside the motor cooling channel 41, so that air as a cooling medium flowing into the motor cooling channel 41 is present. The two thrust plates 13a and 13b, which are constituent members of the motor rotor 28a, and the motor coil 28ba constituting the motor stator 28b flow through the arrangement portion, so that more efficient motor cooling can be performed.

FIG. 5 shows the overall configuration of a refrigeration system apparatus 50 using the turbine unit 5. The refrigeration system device 50 is a system that directly cools air in a space to be cooled 10 such as a freezer as a refrigerant, and a refrigerant flow path 1 extending from an air intake port 1a to an exhaust port 1b respectively opened in the space to be cooled 10. have. The refrigerant flow path 1 is an air circulation path. The refrigerant flow path 1 includes a first heat exchanger 3, a compressor 6 of an air cycle refrigeration cooling turbine unit 5, a second heat exchanger 8, and intermediate heat. An exchanger 9 and an expansion turbine 7 of the turbine unit 5 are provided in this order. The middle of the path from the first heat exchanger 3 to the second heat exchanger 8 is the above-described motor cooling flow path 41 that penetrates the arrangement portion of the motor 28. If the motor cooling flow path 41 is arranged in this way, the air after being discharged from the compressor 6 and cooled by the first heat exchanger 3 is supplied to the motor 28 via the motor cooling flow path 41. Good motor cooling.
The intermediate heat exchanger 9 exchanges heat between the inflow air in the vicinity of the intake port 1a in the same refrigerant flow path 1 and the air that has been heated by the subsequent compression and cooled. The air in the vicinity of 1a passes through the heat exchanger 9a.

  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 a refrigerant flow 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.

  The refrigeration cycle apparatus 50 is a system that keeps the space 10 to be cooled at about 0 ° C. to −60 ° C., and has a pressure of about 1 ° C. from 0 ° C. to −60 ° C. from the space to be cooled 10 to the inlet 1a of the refrigerant flow path 1. 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 for cooling the subsequent air in the refrigerant flow path 1 by the intermediate heat exchanger 9, and the temperature is raised to 30 ° C.

The air at 30 ° C. and 1 atm that has passed through the intermediate heat exchanger 9 is compressed to 1.8 atm by the compressor 6 of the turbine unit 5, and the temperature is raised to about 80 ° C. by this compression. Cooled to 30 ° C. by vessel 3. The 30 ° C. air is cooled to −20 ° C. by the second heat exchanger 8 and the intermediate heat exchanger 9 while being heated to about 50 ° C. for cooling the motor 28. 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 −50 ° C., and discharged from the outlet 1 b to the cooled space 10. The refrigeration cycle apparatus 50 performs such a refrigeration cycle.

  In the refrigeration cycle apparatus 50, in the turbine unit 5, stable high-speed rotation of the main shaft 13 is obtained while maintaining appropriate gaps d1 and d2 between the impellers 6a and 7a, and long-term durability of the bearings 15 and 16 is improved. By improving the life, the long-term durability of the bearings 15 and 16 is improved. Therefore, the reliability of the turbine unit 5 as a whole, and the refrigeration cycle apparatus 50 as a whole, 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.

1 is a cross-sectional view of a turbine unit in which a motor-integrated magnetic bearing device according to an embodiment of the present invention is incorporated. It is II-II arrow sectional drawing in FIG. It is a block diagram which shows an example of the controller for magnetic bearings used for a motor integrated magnetic bearing apparatus. It is a block diagram which shows an example of the controller for motors used for a motor-integrated magnetic bearing apparatus. It is a systematic diagram of the refrigeration cycle apparatus to which the turbine unit of FIG. 1 is applied. It is sectional drawing of the motor arrangement | positioning part in a proposal example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Refrigerant flow path 3 ... 1st heat exchanger 5 ... Turbine unit 6 ... Compressor 6a ... Compressor impeller 7 ... Expansion turbine 7a ... Turbine impeller 8 ... Second heat exchanger 9 ... Intermediate heat exchanger 13 ... Spindles 13a, 13b ... thrust plate 14 ... spindle housings 15, 16 ... rolling bearings 17 ... electromagnets (magnetic bearings)
17A ... Permanent magnet (magnetic bearing)
28 ... Axial gap motor 28a ... Motor rotor 28aa ... Permanent magnet 28b ... Motor stator 28ba ... Motor coil 41 ... Motor cooling flow path 43 ... Rectifying plate 43a ... Tip 50 ... Refrigeration cycle apparatus

Claims (6)

A rolling bearing and a magnetic bearing that support a main shaft provided with a compressor wheel and a turbine wheel, and a motor that rotationally drives the main shaft; the rolling bearing supports a radial load; and the magnetic bearing is an axial load. The electromagnet that supports either or both of the bearing preloads and that constitutes the magnetic bearing is attached to the spindle housing so as to face the flange-shaped thrust plate made of a ferromagnetic material provided on the main shaft in a non-contact manner, A motor-integrated magnetic bearing device in which a rotor of the motor is installed in the spindle housing,
A motor cooling flow path that penetrates the motor arrangement portion in the spindle housing is provided, and the refrigerant flow path of the refrigeration cycle apparatus in which the compressor having the compressor impeller and the expansion turbine having the turbine impeller are interposed, A rectifying plate is attached to the spindle housing to interpose a motor cooling flow path and is located in the motor cooling flow path to change the flow direction of the refrigerant, and the rectification plate changes the flow direction of the changed refrigerant to the motor rotor. A motor-integrated magnetic bearing device characterized by having the same direction as the rotation direction.   The motor-integrated magnetic bearing device according to claim 1, wherein a tip of the rectifying plate is disposed in the vicinity of an outer diameter surface of the motor rotor.   3. The refrigerant flow path of the refrigeration cycle apparatus according to claim 1, wherein the refrigerant flow path includes a heat exchanger that cools the refrigerant discharged from the compressor, and a portion of the refrigerant flow path that is subsequent to the heat exchanger. A motor-integrated magnetic bearing device in which the motor cooling flow path is interposed.   4. The motor according to claim 1, wherein the motor is an axial gap type motor, and a plurality of rotors of the motor are provided at equal pitches in the circumferential direction on the thrust plate and the thrust plate. A motor-integrated magnetic bearing device composed of a single permanent magnet.   The thrust plate according to claim 3, wherein the two thrust plates are opposed to the main shaft, the motor coil is disposed between the two thrust plates, the permanent magnets are disposed on the two thrust plates, The electromagnets of the magnetic bearings are arranged to face opposite surfaces of the thrust plate opposite to each other, and the motor cooling flow path has the two thrust plates and the motor coil located inside The motor-integrated magnetic bearing device.   The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the refrigeration cycle apparatus compresses the inflow air as the refrigerant by the compressor, cooling by another heat exchanger, adiabatic expansion by the expansion turbine, Motor-integrated magnetic bearing device that is an air cycle refrigeration cooling system that performs air conditioning or refrigeration in sequence.

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