JP2008193879A - Magnetic bearing device integrated with electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic bearing device integrated with a motor, capable of improving long-term durability of a ball bearing against a thrust load and enlarging the size of a permanent magnet to materialize high-speed rotation and high performance. <P>SOLUTION: Two electric magnets 17 are arranged outside in the axial direction of two thrust boards 13a, 13b mounted on a main shaft 13 in line with the axial direction to constitute a magnetic bearing unit, and an axial-gap motor 28 is disposed in between two thrust boards 13a, 13b as a motor unit. A reinforcing member HB, comprising a reinforced fiber, is provided extending from the outer periphery of a flange portion to that of a non-flange portion, on each of the outer peripheral surfaces of the thrust boards 13a, 13b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetic bearing device used for an air cycle refrigeration cooling turbine unit and the like, and more particularly, to a motor-integrated magnetic bearing device that reinforces the outer peripheral surface of a thrust plate and the like to achieve high speed rotation and high performance.

  Since the air cycle refrigeration cooling system uses air as a refrigerant, energy efficiency is insufficient as compared with the case of using chlorofluorocarbon, ammonia gas, or the like, 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.
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 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, the present inventors have developed a motor-integrated magnetic bearing device as shown in FIG. 11 as a solution to the above problem. This motor-integrated magnetic bearing device rolls the radial load of the main shaft 53 in an air cycle refrigeration cooling turbine unit in which a compressor impeller 46a of the compressor 46 and a turbine impeller 47a of the expansion turbine 47 are attached to both ends of the main shaft 53. The axial loads are supported by the electromagnets 57 by the bearings 55 and 56, respectively, and the compressor impeller 46a is rotationally driven by the driving force of the motor 68 provided coaxially with the main shaft 53 and the driving force of the turbine impeller 47a. Is. The electromagnet 57 that supports the axial load is disposed so as to face the thrust plate 53a that is perpendicular and coaxial with the main shaft 53 in a non-contact manner, and is used for a magnetic bearing according to the output of the sensor 58 that detects the axial force. It is controlled by the controller 59. The motor 68 is of an axial gap type, and a motor rotor 68a is formed on another thrust plate 53b provided perpendicularly and coaxially to the main shaft 53, and a motor stator 68b is disposed so as to face the motor rotor 68a in the axial direction. Configured. The motor 68 is controlled by a motor controller 69 independently of the electromagnet 57.

  According to the motor-integrated magnetic bearing device configured as described above, since the thrust force applied to the main shaft 53 is supported by the electromagnet 57, the thrust force acting on the rolling bearings 55 and 56 is reduced while suppressing an increase in torque without contact. be able to. As a result, the minute gaps between the respective impellers 46a and 47a and the housings 46b and 47b can be kept constant, and the long-term durability of the rolling bearing against the load of the thrust load can be improved.

However, in the motor-integrated magnetic bearing device configured as described above, the centrifugal force of the permanent magnet adhered to the thrust plate 53a during high-speed rotation is large, and a large stress is applied to the collar portion for fixing the permanent magnet formed on the outer peripheral portion of the thrust plate. appear. In this motor-integrated magnetic bearing device, it is necessary to increase the size of the permanent magnet for further high-speed rotation and higher performance. As the centrifugal stress increases due to the increase in the size of the permanent magnet, it is necessary to take measures such as increasing the tensile strength of the buttocks.
Further, the applicant of the present application has proposed a technique for carburizing and quenching the stress concentration portion, but the tensile strength is insufficient for increasing the speed and expanding the size of the permanent magnet.

  An object of the present invention is to improve the long-term durability of a rolling bearing against a thrust load, and to increase the size of a permanent magnet for high-speed rotation and high performance. It is to provide a bearing device.

  A motor-integrated magnetic bearing device according to the present invention uses a rolling bearing and a magnetic bearing in combination, the rolling bearing supports a radial load, the magnetic bearing supports one or both of an axial load and a bearing preload, and The electromagnet constituting the 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, and the thrust plate has an electromagnet target formed on one side. A permanent magnet for the motor rotor is disposed on the other surface, and a motor stator is disposed opposite to the permanent magnet and attached to the spindle housing. The main shaft is driven by the Lorentz force between the motor rotor and the motor stator. An axial gap type coreless motor that rotates the thrust plate, the thrust plate Provided on the outer peripheral part of the side surface is a flange part that supports the outer peripheral edge part of the permanent magnet, and provided with a reinforcing member made of a reinforcing fiber material from the outer peripheral part of the peripheral part of the thrust plate to the outer peripheral part of the non-protrusive part. It is characterized by that.

  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 when only the magnetic bearing is supported is avoided.

  Moreover, the collar part which supports the outer peripheral part of a permanent magnet is provided in the outer peripheral part of the side surface of each thrust board. Since the reinforcing member made of the reinforcing fiber material is provided from the outer peripheral part of the flange part to the outer peripheral part of the non-protrusion part on the outer peripheral surface of each thrust plate, the tensile strength of the flange part is increased compared to the conventional one, and the permanent magnet It is possible to increase the size to achieve high speed rotation and high performance. A large stress is generated in the buttocks during high-speed rotation, but this stress can be allowed by the reinforcing member. Moreover, it is possible to reliably prevent the permanent magnets from being scattered.

  In the present invention, the reinforcing fiber material is preferably a carbon fiber in the form of a filament (that is, a fine thread) or a sheet. In the case of a filament-like carbon fiber, the carbon fiber can be suitably wound around a circumferential groove formed on the outer peripheral surface of each thrust plate. In the case of a sheet-like carbon fiber, this carbon fiber can be wound within the width of the outer peripheral surface of the thrust plate.

In the present invention, a circumferential groove may be formed on the outer peripheral surface of each thrust plate, and a reinforcing fiber material may be wound around the circumferential groove. In this case, the reinforcing fiber material can be quickly and surely wound around the circumferential groove, so that the number of work steps can be reduced.
In the present invention, two thrust plates may be provided side by side on the main shaft, two electromagnets may be provided on the outer sides in the axial direction of the two thrust plates, and the motor stator may be disposed at a position sandwiched between the two thrust plates. . In this case, the magnetic bearing unit and the motor unit can have a compact integrated structure. Therefore, the shaft length of the main shaft can be shortened, the natural frequency of the main shaft can be increased accordingly, and the main shaft can be rotated at high speed.

  The motor-integrated magnetic bearing device of the present invention uses a rolling bearing and a magnetic bearing in combination, the rolling bearing supports a radial load, the magnetic bearing supports one or both of an axial load and a bearing preload, The electromagnet constituting 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 without contact, and the thrust plate has an electromagnet target on one side. A permanent magnet for the motor rotor is disposed on the outer peripheral portion of the other surface, and a motor stator is disposed opposite to the permanent magnet and attached to the spindle housing, and between the motor rotor and the motor stator. Having an axial gap type coreless motor that rotates the spindle by the Lorentz force of Over the outer peripheral edge portion of the permanent magnet from the outer peripheral surface of serial thrust plate, characterized in that a reinforcing member made of a reinforcing fiber material.

  According to this configuration, since the flange portion of the thrust plate is omitted and the reinforcing member made of the reinforcing fiber material is provided directly from the outer peripheral surface of the thrust plate to the outer peripheral edge portion of the permanent magnet, the thrust member provided with the flange portion is provided. The structure of the thrust plate can be simplified as compared with the plate, and the tensile strength of the thrust plate itself can be increased. In particular, since the centrifugal force of the permanent magnet can be directly received by the reinforcing member, the structure of the thrust plate can be simplified and the manufacturing cost can be reduced. In addition, the same operations and effects as the invention according to claim 1 are provided.

In the present invention, one or a plurality of circumferential grooves may be formed from the outer peripheral surface of the thrust plate to the outer peripheral edge of the permanent magnet, and the reinforcing fiber material may be wound around the circumferential grooves. In this case, the reinforcing fiber material can be quickly and surely wound around the circumferential groove, so that the number of work steps can be reduced. When a plurality of circumferential grooves are formed, the tensile strength can be further increased by alternately winding reinforcing fiber materials around the circumferential grooves.
In the present invention, two thrust plates may be provided side by side on the main shaft, two electromagnets may be provided on the outer sides in the axial direction of the two thrust plates, and the motor stator may be disposed at a position sandwiched between the two thrust plates. . In this case, the magnetic bearing unit and the motor unit can have a compact integrated structure. Therefore, the shaft length of the main shaft can be shortened, the natural frequency of the main shaft can be increased accordingly, and the main shaft can be rotated at high speed.

  In the motor-integrated magnetic bearing device of the present invention, the reinforcing member made of the reinforcing fiber material is provided from the outer peripheral portion of the flange portion to the outer peripheral portion of the non-protruding portion on the outer peripheral surface of the thrust plate. It is possible to increase the tensile strength of the portion and increase the size of the permanent magnet to achieve high speed rotation and high performance. Moreover, it is possible to reliably prevent the permanent magnets from being scattered. In addition, since a rolling bearing and a magnetic bearing are used together, the rolling bearing supports a radial load, and the magnetic bearing supports one or both of an axial load and a bearing preload. It can be done and long-term durability of the rolling bearing can be secured.

  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. Match. The material of the main shaft 13 is low carbon steel with good magnetic properties.

In FIG. 1, the compressor 6 has a compressor housing 6b facing the compressor impeller 6a with a small gap d1, and compresses air sucked in the axial direction from the suction port 6c in the center by the compressor impeller 6a. And it discharges as shown by the arrow 6d 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 bearings 15 and 16 in the radial direction, and either or both of the axial load and the bearing preload applied to the main shaft 13 are magnetic bearings. An axial gap motor 28 that is supported by an electromagnet 17 and that rotates the main shaft 13 is provided. 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 according to the output of the sensor 18, and the electromagnet 17. A motor controller 29 for controlling the motor 28;

  The electromagnet 17 is in non-contact with each surface of the two flange-shaped thrust plates 13a and 13b made of a ferromagnetic material that is provided perpendicularly and coaxially to the main shaft 13 so as to be aligned in the axial direction at the axial intermediate portion of the main shaft 13. A pair is installed in the spindle housing 14 so as to face each other. Specifically, one of the electromagnets 17 constituting the magnetic bearing unit is opposed to this one surface in a non-contact manner with the one surface facing the expansion turbine 7 of the thrust plate 13a located near the expansion turbine 7 as an electromagnet target. Installed in the spindle housing 14. Further, the other electromagnet 17 constituting the magnetic bearing unit is installed on the spindle housing 14 so as to face the one surface of the thrust plate 13b located near the compressor 6 toward the compressor 6 side, with the electromagnet target being non-contacted. Is done.

  The motor 28 is a motor unit including a motor rotor 28 a provided on the main shaft 13 along with the electromagnet 17, and a motor stator 28 b facing the motor rotor 28 a in the axial direction. Specifically, the motor rotor 28a that constitutes one part of the motor unit is arranged at a constant pitch in the circumferential direction on each side of the main shaft 13 opposite to the side where the electromagnets 17 of the thrust plates 13a and 13b face each other. By arranging the permanent magnets 28aa arranged side by side, a pair of left and right are configured. Thus, between the permanent magnets 28aa arranged opposite to each other in the axial direction, the magnetic poles are set to be 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 electromagnet target of the permanent magnet 28aa. it can.

  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 shown in FIGS. 2 and 3, the main shaft 13 is divided into, for example, two main shaft divided bodies 13A and 13B between two thrust plates 13a and 13b, and both main shaft divided bodies 13A and 13B are coupled to each other. Has been integrated. One main shaft divided body 13A has a round shaft-like fitting convex portion at the axial center portion of the end surface S1 serving as a divided surface, and the other main shaft divided body 13B is formed on the end surface S1 serving as the divided surface. It has a circular fitting recess that fits on the outer periphery of the part. Both the main shaft split bodies 13A and 13B are constrained in the radial direction and the axial direction by the fitting on the peripheral surface of the fitting convex portion and the fitting concave portion and the butting of the end surface S1 serving as the split surface, and The shafts are coupled to each other by bolts or the like not shown. The bolt is a double-cut bolt, and a screw hole formed at the center of the front end surface of the fitting convex portion of one main shaft divided body 13A and a screw formed at the center of the bottom surface of the fitting concave portion of the other main shaft divided body 13B. Screwed over the hole. Each of the spindle divided bodies 13A and 13B is subjected to a heat treatment for hardening such as quenching of a steel material, for example, and the bolt is made of raw steel that is not subjected to a heat treatment for hardening. ing.

  The opposing surfaces of the thrust plates 13a, 13b of the main shaft division bodies 13A, 13B are shaped to have an annular recess 43 between the vicinity of the center and the outer peripheral edge, and the motor rotor 28a is configured in the recess 43. A permanent magnet 28aa is attached by adhesion or the like. In addition, a flange TB for supporting the outer peripheral edge portion 28ab of each permanent magnet 28aa is provided on the outer peripheral portion of the side surface of each thrust plate 13a, 13b.

Further, a reinforcing member HB made of a reinforcing fiber material is provided from the outer peripheral portion TBa of the flange portion TB to the outer peripheral portion NTBa of the non-protruded portion NTB on the outer peripheral surfaces of the thrust plates 13a and 13b. In particular, this reinforcing member increases the tensile strength of the flange portion TB. As the reinforcing fiber material, for example, a carbon fiber can be applied. However, the reinforcing fiber material is not necessarily limited to carbon fiber, and for example, boron fiber or Kevlar fiber having high tensile strength may be applied.
The reinforcing member HB is manufactured by, for example, a sheet winding method or a filament winding method. In this embodiment, a sheet winding method is applied.

Here, the sheet winding method and the like will be described.
For example, a sheet made of carbon fiber or the like is impregnated with a thermosetting resin to prepare a semi-cured material, that is, a prepreg sheet. Next, this prepreg sheet is wound around a cylindrical mold (not shown), and then placed in a heat curing furnace to be formed into a pipe shape. At this time, by laminating a plurality of prepreg sheets in consideration of the fiber angle, anisotropy of strength due to the fiber orientation direction can be avoided and desired mechanical properties can be obtained. In this way, the sheet body formed into a pipe shape is press-fitted from the outer peripheral portion TBa of the flange portion TB to the outer peripheral portion NTBa of the non-protruded portion NTB to obtain the reinforcing member HB. In this case, a sheet body that is easier to handle than the prepreg sheet can be manufactured in parallel with the thrust plates 13a and 13b, and mass production can be achieved. In particular, by applying the sheet winding method, the sheet body can be housed and wound within the width H1 of the outer peripheral surface of the thrust plates 13a and 13b. In other words, a sheet body that fits within the width H1 of the outer peripheral surface of the thrust plates 13a and 13b is prepared using the sheet winding method, and the outer periphery of the thrust plates 13a and 13b is processed without post-processing the sheet body. It can be securely provided within the width H1 of the surface. In addition, an adhesive etc. may be apply | coated between the inner peripheral surface of a sheet | seat body, and the outer peripheral part of eaves part TB and non eaves part NTB, and a reinforcement member may be fixed.

  In the present embodiment, the sheet body after being cured in the heat curing furnace is provided on the outer peripheral surfaces of the thrust plates 13a and 13b, but is not limited to this method. For example, a method of obtaining a reinforcing member HB by winding a semi-cured prepreg sheet around the outer peripheral surface of a thrust plate and then curing it may be applied. In this case, the trouble of press-fitting the sheet body or applying an adhesive or the like can be omitted, and the number of work steps can be reduced. Furthermore, since the prepreg sheet is wound around the outer peripheral surface of the thrust plates 13a and 13b instead of the cylindrical mold, the cylindrical mold itself can be omitted, and the equipment cost can be reduced correspondingly. Thereby, the manufacturing cost of the whole magnetic bearing device can be reduced.

  In FIG. 1, 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 or angular 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.

As shown in FIG. 3, the main shaft 13 is a stepped shaft having, for example, a large diameter portion 13c, a medium diameter portion 13e, 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.
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. In this embodiment, the non-contact seals 21 and 22 are labyrinth seals in which a plurality of circumferential grooves are formed on the inner diameter surface of the spindle housing 14 in the axial direction, but other non-contact seal means may be used.

  The sensor 18 is provided on the stationary side in the vicinity of the bearing 16 on the turbine impeller 7a side, that is, on the spindle housing 14 side. The outer ring 16 b of the bearing 16 provided with the sensor 18 in the vicinity thereof is fitted in the bearing housing 23 in a fixed state. The bearing housing 23 has an inner flange 23a that is formed in a ring shape and engages with the width surface of the outer ring 16b of the bearing 16 at one end, and is movable in the axial direction on an inner diameter surface 24 provided on the spindle housing 14. It is mated. The inner collar 23a is provided at the center side end in the axial direction.

  The sensor 18 is provided on the stationary side in the vicinity of the bearing 16 on the turbine blade 7a side, that is, on the spindle housing 14 side. The outer ring 16 b of the bearing 16 provided with the sensor 18 in the vicinity thereof is fitted in the bearing housing 23 in a fixed state. The bearing housing 23 has an inner flange 23a that is formed in a ring shape and engages with the width surface of the outer ring 16b of the bearing 16 at one end, and is movable in the axial direction on an inner diameter surface 24 provided on the spindle housing 14. It is mated. The inner collar 23a is provided at the center side end in the axial direction.

  The sensors 18 are distributed and arranged at a plurality of locations (for example, two locations) in the circumferential direction around the main shaft 13, the width surface of the bearing housing 23 on the inner flange 23 a side, and one electromagnet 17 that is a member fixed to the spindle housing 14. It is interposed between. The sensor 18 is applied with preload by a sensor preload spring 25. The sensor preload spring 25 is housed in a housing recess provided in the spindle housing 14 and biases the outer ring 16 b of the bearing 16 in the axial direction, and preloads the sensor 18 via the outer ring 16 b and the bearing housing 23. . The sensor preload spring 25 is composed of, for example, coil springs provided at a plurality of locations in the circumferential direction around the main shaft 13.

  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 so as to be movable in the axial direction, and the bearing preload spring 26 is interposed between the outer ring 15 b and the spindle housing 14. 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 includes coil springs and the like provided at a plurality of locations in the circumferential direction around the main shaft 13, and is accommodated in receiving recesses provided in the spindle housing 14. 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 (sensor preload spring 25, bearing preload spring 26, bearing housing 23, etc.), and a motor unit (electromagnet 17 and motor 28). ) Formed 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 combined spring formed by 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 of FIG. 4 shown in the block diagram, the detection outputs P1 and P2 of each 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. By controlling the electromagnet 17 by performing a proportional integration (or proportional) process in which the calculated deviation is appropriately set according to the turbine unit 5 by the PI compensation circuit (or P compensation circuit) 33. The signal is calculated. The output of the PI compensation circuit (or P compensation circuit) 33 is input to power circuits 36 and 37 that drive the electromagnets 17 1 and 17 2 in each direction via diodes 34 and 35. The electromagnets 17 1 and 17 2 are a pair of electromagnets 17 facing the thrust plate 13a shown in FIG. 1, and only the attractive force acts. Therefore, the direction of current is determined in advance by the diodes 34 and 35, and the two electromagnets 17 are used. 1 and 17 2 are selectively driven.

  In the motor controller 29 of FIG. 5 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 applied to, for example, an air cycle refrigeration cooling system, and is compressed by a compressor 6 so that air as a cooling medium can be efficiently heat-exchanged by a heat exchanger (not shown here) at a subsequent stage. Then, the temperature is increased, and the air cooled by the heat exchanger in the subsequent stage is cooled and discharged by adiabatic expansion to a target temperature, for example, a very low temperature of about −30 ° C. to −60 ° C. by the expansion turbine 7. Used for.

  In such a use example, the turbine unit 5 includes a compressor impeller 6a and a turbine impeller 7a fitted on the main shaft 13 common to the thrust plate 13a and the motor rotor 28a, and the power of the motor 28 and the turbine impeller 7a. The compressor impeller 6a is driven by either one or both of the power generated in the above. 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.

  That is, 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 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, 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.

  Two electromagnets 17 are arranged on the axially outer side of the two thrust plates 13a, 13b provided on the main shaft 13 side by side in the axial direction to constitute a magnetic bearing unit, and at a position sandwiched between the thrust plates 13a, 13b. By arranging the axial gap type motor 28 to constitute the motor unit, the magnetic bearing unit and the motor unit are made into a compact integrated structure. Therefore, the shaft length of the main shaft 53 can be shortened, and the natural frequency of the main shaft 13 can be reduced accordingly. It becomes high and the main shaft 13 can be rotated at high speed.

  Further, in this motor-integrated magnetic bearing device, since the motor stator 28b is disposed between the two thrust plates 13a and 13b of the main shaft 13, both the motor stator 28b and the main shaft 13 are integrated members. As shown in FIG. 2, the main shaft 13 is divided into two parts between the two thrust plates 13a and 13b, and both main shaft divided bodies 13A and 13B are combined with each other. The motor can be assembled so that the integral motor stator 28b is interposed between the thrust plates 13a and 13b. Further, since the main shaft 13 is divided between the two thrust plates 13a and 13b, the permanent magnet 28aa serving as the motor rotor 28a attached to the thrust plates 13a and 13b can be obtained even if the gap between the thrust plates 13a and 13b is narrow. It can be easily attached to the thrust plates 13a and 13b. That is, the permanent magnet 28aa can be attached in a state in which the main spindle divided bodies 13A and 13B are separated, and the permanent magnet 28aa can be attached regardless of the size of the gap between the thrust plates 13a and 13b.

  Unlike the case where the motor stator 28b has a divided structure, the main shaft 13 has a divided structure. Even if the main shaft 13 rotates at a high speed, the main shaft 13 itself has a divided structure that is divided between two thrust plates. Therefore, unlike the case where the thrust plates 13a and 13b are divided from the main shaft 13, a firm connection is achieved. The structure can be designed freely, and it is possible to solve the problem of insufficient strength at the connecting part of the main spindle split part during high-speed rotation.

In this embodiment, both main shaft split bodies 13A and 13B are provided with a fitting convex part and a fitting concave part to form a so-called stamped joint, and the abutting surface of the end surface S1 which becomes a split surface, the fitting convex part and the fitting Since it restrains by 2 surfaces with the surrounding surface with which a recessed part fits, and fastens with the said volt | bolt, both main shaft division bodies 13A and 13B can be couple | bonded firmly.
The bolt may be provided integrally with one of the main shaft division bodies 13A and 13B. However, if the main shaft division bodies 13A and 13B are separate parts, the material of the bolt can be freely selected. . In this example, the main shaft 13 is subjected to heat treatment for improving hardness such as quenching in order to ensure rigidity, etc. However, if heat treatment is performed with the main shaft divided bodies 13A and 13B and the bolt as an integrated structure, the bolt portion is There is a risk of lack of brittleness. However, since the bolt is made of a non-quenched material as a separate member, the problem of insufficient brittleness is solved, and highly reliable fastening without the problem of unexpected breakage of the bolt can be performed.

  In this embodiment, in particular, the reinforcing member HB made of carbon fiber is provided from the outer peripheral portion TBa of the flange portion TB to the outer peripheral portion NTBa of the non-protruded portion NTB on the outer peripheral surface of each thrust plate 13a, 13b. It is possible to increase the tensile strength of the flange portion TB and increase the size of the permanent magnet 28aa to achieve higher speed rotation and higher performance. A large stress is generated in the flange TB during high-speed rotation, but this stress can be allowed by the reinforcing member HB. Moreover, scattering of the permanent magnet 28aa from the thrust plates 13a and 13b can be reliably prevented.

  When the reinforcing member HB is provided, by applying a sheet winding method, the sheet body is accommodated within the width H1 of the outer peripheral surface of the thrust plates 13a and 13b, that is, between the axial end of the outer peripheral surface and the other end. Can be rolled. Thus, interference between the reinforcing member HB and the motor stator 28b or the electromagnet 17 can be prevented. Further, post-processing such as cutting one side edge and the other side edge of the sheet body is not required, and the number of man-hours can be reduced.

  FIG. 6 shows the overall configuration of an air cycle refrigeration cooling system using the turbine unit 5. This air cycle refrigeration cooling system is a system that directly cools air in a space to be cooled 10 such as a refrigeration warehouse as a refrigerant, and circulates air from an air intake port 1a to a discharge port 1b respectively opened in the space to be cooled 10. It has path 1. In this air circulation path 1, pre-compression means 2, first heat exchanger 3, compressor 6 of air cycle refrigeration cooling turbine unit 5, second heat exchanger 3, intermediate heat exchanger 9, and the turbine unit Five expansion turbines 7 are 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. The air in the vicinity of 1a passes through the heat exchanger 9a.

  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. Note that an air cycle refrigeration cooling system that does not include the pre-compression means 2 may be used.

  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 is 1 atmosphere at about 0 ° C. to −60 ° C. from the space to be cooled 10 to the inlet 1a of the air circulation path 1. Inflow of air. Note that the numerical values of temperature and atmospheric pressure shown below are examples that serve as a rough standard. 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 70 ° C. by the compression. Since the 1st heat exchanger 3 should just cool the air of 70 degreeC which raised temperature, even if it is cold water about normal temperature, it can cool efficiently and it cools to 40 degreeC.

The air at 40 ° C. and 1.4 atm cooled by heat exchange is compressed to 1.8 atm by the compressor 6 of the turbine unit 5, and the second heat is increased to about 70 ° C. by this compression. It is cooled to 40 ° C. by the exchanger 8. 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.

  In this air cycle refrigeration cooling system, in the turbine unit 5, 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 of the bearings 15 and 16 can be improved. Since the long-term durability of the bearings 15 and 16 is improved by obtaining the improvement and the improvement of the life, the reliability of the turbine unit 5 as a whole 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.

  Next, another embodiment of the present invention will be described with reference to FIGS. 7 and 8 are cross-sectional views of the main parts of other thrust plates and the like used in the motor-integrated magnetic bearing device of this embodiment. In the following description, the same reference numerals are given to portions corresponding to the matters described in the preceding forms in each embodiment, and overlapping description may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  In this embodiment, a collar portion TB that supports the outer peripheral edge portion 28ab of each permanent magnet 28aa is provided on the outer peripheral portion of the side surface of each thrust plate 13a, 13b. Further, a circumferential groove EM having a concave cross section is formed on the outer peripheral surface of each thrust plate 13a, 13b, and a reinforcing member HB made of carbon fiber is provided in the circumferential groove EM. In this embodiment, the reinforcing member HB is manufactured by a filament winding method.

Here, the filament winding method and the like will be described.
A filament-like carbon fiber impregnated with a thermosetting resin is wound and molded so as to fit in the circumferential groove EM of each thrust plate 13a, 13b. Next, the molded body is cured in a heat curing furnace to obtain a reinforcing member HB as a finished product. According to this method, the carbon fiber can be wound around the circumferential groove EM by various winding patterns. Thereby, mechanical properties such as tensile strength of the reinforcing member HB can be easily adjusted. Therefore, the tensile strength of the collar portion TB can be easily increased. Further, in this embodiment, since the carbon fiber is wound around the circumferential groove EM having a concave cross section, a part of the reinforcing member HB does not undesirably protrude in one or the other in the axial direction. Interference between the reinforcing member HB and the motor stator 28b or the electromagnet 17 can be prevented. Other operations and effects similar to those of the above-described embodiment shown in FIGS.

Next, still another embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 9, in this embodiment, the flange portion of each thrust plate 13a, 13b is omitted, and the outer peripheral surface of the thrust plate 13a, 13b and the outer peripheral portion of the permanent magnet 28aa are connected on the same peripheral surface. Provided. A reinforcing member HB made of carbon fiber is provided from the outer peripheral surface of each thrust plate 13a, 13b to the outer peripheral edge of the permanent magnet 28aa. The reinforcing member HB may be provided using any one of the above-described sheet winding method and filament winding method. Further, as shown in FIG. 10, a plurality of circumferential grooves EMa are formed at regular intervals in the axial direction from the outer peripheral surface of each thrust plate 13a, 13b to the outer peripheral edge of the permanent magnet 28aa. A filament-like carbon fiber impregnated with thermosetting resin may be wound around EMa and molded, and then the molded body may be cured. A plurality of circumferential grooves EMa may be formed at appropriate intervals in the axial direction.

  According to this configuration, since the flange portion of each thrust plate 13a, 13b is omitted and the reinforcing member HB is provided directly from the outer peripheral surface of each thrust plate 13a, 13b to the outer peripheral edge portion of the permanent magnet 28aa, The structure of each thrust plate 13a, 13b can be simplified as compared with the thrust plate provided with the portion, and the tensile strength of each thrust plate itself can be increased. In particular, since the centrifugal force of the permanent magnet 28aa can be directly received by the reinforcing member HB, the structure of each thrust plate 13a, 13b can be simplified and the manufacturing cost can be reduced.

  In addition, as shown in FIG. 10, when a carbon fiber is wound around a plurality of circumferential grooves EMa, the carbon fibers are held in the grooves in the middle of winding due to the frictional resistance between the circumferential grooves EMa and the carbon fibers and loosen. Therefore, the carbon fiber can be quickly and surely wound around the circumferential groove EMa, so that the number of work steps can be reduced. Further, by alternately winding the carbon fiber around each circumferential groove EMa, it is possible to further increase the tensile strength of the reinforcing member HB. Other operations and effects similar to those of the above-described embodiment shown in FIGS. As another embodiment of the present invention, instead of a plurality of circumferential grooves, one circumferential groove is formed from the outer peripheral surface of each thrust plate to the outer peripheral edge portion of the permanent magnet, and this circumferential groove is impregnated with a thermosetting resin. You may shape by winding the made carbon fiber.

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 sectional drawing of the principal parts, such as a main axis | shaft and a thrust board, in the same turbine unit. FIG. 3A is a cross-sectional view of the thrust plate and the like, FIG. 3A is a cross-sectional view of a main part of the thrust plate and the like, and 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 air cycle refrigeration cooling system to which the turbine unit is applied. It is sectional drawing of principal parts, such as another thrust board concerning this Embodiment. It is sectional drawing of the principal parts, such as the thrust board. It is sectional drawing of the principal parts, such as the further another thrust board concerning embodiment of this invention. It is sectional drawing of the principal part which formed the several circumferential groove from the outer peripheral surface of the thrust plate to the outer peripheral edge part of a permanent magnet, and wound carbon fiber in this circumferential groove. It is sectional drawing of the magnetic bearing apparatus of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 13 ... Main shaft 13a, 13b ... Thrust board 14 ... Spindle housing 15, 16 ... Bearing 17 ... Electromagnet 28 ... Coreless motor 28a ... Motor rotor 28aa ... Permanent magnet 28b ... Motor stator TB ... Reinforcement member EM ... Circumferential groove

Claims (7)

A rolling bearing and a magnetic bearing are used in combination, the rolling bearing supports the radial load, the magnetic bearing supports one or both of the axial load and the bearing preload, and the electromagnet constituting the magnetic bearing is a strong force provided on the main shaft. It is attached to the spindle housing so as to face the flange-shaped thrust plate made of magnetic material without contact,
In the thrust plate, an electromagnet target is formed on one side, a permanent magnet for a motor rotor is arranged on the other side, a motor stator is arranged facing the permanent magnet, and is attached to the spindle housing. It has an axial gap type coreless motor that rotates a main shaft by Lorentz force between the motor rotor and the motor stator,
Provided on the outer peripheral portion of the side surface of the thrust plate is a flange portion that supports the outer peripheral edge portion of the permanent magnet, and is made of a reinforcing fiber material from the outer peripheral portion of the flange portion to the outer peripheral portion of the non-ridge portion on the outer peripheral surface of the thrust plate. A motor-integrated magnetic bearing device comprising a reinforcing member.   2. The motor-integrated magnetic bearing device according to claim 1, wherein the reinforcing fiber material is a filament-like or sheet-like carbon fiber.   3. The motor-integrated magnetic bearing device according to claim 1, wherein a circumferential groove is formed on an outer peripheral surface of the thrust plate, and a reinforcing fiber material is wound around the circumferential groove.   4. The position according to claim 1, wherein two thrust plates are provided side by side on the main shaft, two electromagnets are provided on the axially outer sides of the two thrust plates, and are sandwiched between the two thrust plates. A motor-integrated magnetic bearing device in which the motor stator is disposed. A rolling bearing and a magnetic bearing are used in combination, the rolling bearing supports the radial load, the magnetic bearing supports one or both of the axial load and the bearing preload, and the electromagnet constituting the magnetic bearing is a strong force provided on the main shaft. It is attached to the spindle housing so as to face the flange-shaped thrust plate made of magnetic material without contact,
The thrust plate has an electromagnet target formed on one side, a permanent magnet for a motor rotor is arranged on the outer periphery of the other side, and a motor stator is arranged facing the permanent magnet and attached to the spindle housing. And having an axial gap type coreless motor that rotates a main shaft by Lorentz force between the motor rotor and the motor stator,
A motor-integrated magnetic bearing device comprising a reinforcing member made of a reinforcing fiber material extending from an outer peripheral surface of the thrust plate to an outer peripheral edge of a permanent magnet.   6. The motor-integrated magnetic bearing device according to claim 5, wherein one or a plurality of circumferential grooves are formed from the outer peripheral surface of the thrust plate to the outer peripheral edge of the permanent magnet, and a reinforcing fiber material is wound around the circumferential grooves. .   7. The motor stator according to claim 5, wherein two thrust plates are provided side by side on the main shaft, two electromagnets are provided on the outer sides in the axial direction of the two thrust plates, and the motor stator is positioned between the two thrust plates. Arranged motor-integrated magnetic bearing device.

Images