Bearing system, turbo-compressor, refrigeration system, Abnormality detection method for bearing system

Abstract

In a first operation, the control section (80) controls the support section (11) so that the shaft (20) moves in the circumferential direction of the bottoming bearing (50) while being in contact with the inner peripheral surface of the bottoming bearing (50). In a second operation, in a case where a waveform representing a change in a data value, which changes in accordance with a change in the amplitude of a signal output from the displacement sensor (70) when the first operation is performed, does not have line symmetry, the control section (80) outputs first information representing an abnormality.

Description

Technical Field

[0001] This disclosure relates to bearing systems, turbo compressors, refrigeration systems, and methods for detecting anomalies in bearing systems. Background Technology

[0002] Patent Document 1 discloses a bearing device comprising a magnetic bearing and a bottom-contact bearing. The magnetic bearing uses magnetic force to support the rotating shaft in a non-contact manner. The bottom-contact bearing is an auxiliary bearing that protects the magnetic bearing.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2024-017670 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In a bearing system like that in Patent Document 1, due to dimensional deviations of the constituent components, assembly errors, or other reasons, an abnormal contact may occur where "at least one of the shaft and the elements that rotate with the shaft" comes into contact with other parts that are not the bottom bearing before the shaft comes into contact with the bottom bearing.

[0008] Methods for solving problems

[0009] The first aspect of this disclosure relates to a bearing system comprising: a shaft 20; a support portion 11 that supports the shaft 20 in a non-contact manner using electromagnetic force; a bottom bearing 50 that supports the shaft 20 by contacting the shaft 20 when the support portion 11 is not supporting the shaft 20 in a non-contact manner; a displacement sensor 70 disposed around the shaft 20 and outputting a signal whose amplitude varies according to the distance between the displacement sensor 70 and the shaft 20; and a control unit 80 that performs a first action and a second action, wherein in the first action, the support portion 11 is controlled such that the shaft 20 moves circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, and in the second action, if the waveform representing the change in data value does not have linear symmetry, a first message indicating an anomaly is output, wherein the data value changes according to the amplitude change of the signal output from the displacement sensor 70 when the first action is performed.

[0010] In the first embodiment, if abnormal contact occurs in the bearing system 10, during the period of abnormal contact during the first operation, the shaft 20 cannot move circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Thus, if abnormal contact occurs in the bearing system 10, the symmetry of the increase and decrease in the distance between the shaft 20 and the displacement sensor 70 is disrupted, resulting in a waveform representing the amplitude change of the signal output from the displacement sensor 70 lacking linear symmetry. Therefore, since the waveform representing the change in data value according to the amplitude change of the signal output from the displacement sensor 70 during the first operation lacks linear symmetry, outputting the first information can notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0011] The bearing system of the second aspect of this disclosure includes a first displacement sensor 70a and a second displacement sensor 70b, which are disposed around the shaft 20 and output signals whose amplitude varies according to the distance between them and the shaft 20. The position of the second displacement sensor 70b in the circumferential direction is different from the position of the first displacement sensor 70a in the circumferential direction. The displacement sensor 70 is either the first displacement sensor 70a or the second displacement sensor 70b. The control unit 80 monitors a first data value and a second data value during the second operation. The first data value changes according to the amplitude change of the signal output from the first displacement sensor 70a when the first operation is performed, and the second data value changes according to the amplitude change of the signal output from the second displacement sensor 70b when the first operation is performed.

[0012] In the second approach, by monitoring both the first and second data values, the first information can be output with higher precision compared to monitoring only one data value (a data value that changes according to the amplitude variation of the signal output from the displacement sensor 70). This allows for highly accurate notification of an anomaly (specifically, abnormal contact) occurring in the bearing system 10.

[0013] In the second type of bearing system disclosed herein, during the second operation, if the waveform representing the change of the first data value or the waveform representing the change of the second data value does not have the stated line symmetry, the control unit 80 outputs the first information.

[0014] In the third method, even if line symmetry appears in the waveform representing the change in data value corresponding to one of the first displacement sensor 70a and the second displacement sensor 70b, the waveform representing the change in data value corresponding to the other of the first displacement sensor 70a and the second displacement sensor 70b is no longer linear. Therefore, by monitoring the waveform representing the change in the first data value and the waveform representing the change in the second data value, it is possible to notify with high precision that an anomaly (specifically, abnormal contact) has occurred in the bearing system 10.

[0015] The bearing system of the fourth aspect of this disclosure is a bearing system of any of the first to third aspects, including a magnetic bearing 30 having a plurality of electromagnets 35 disposed around the shaft 20, and supporting the shaft 20 in a non-contact manner by means of the combined electromagnetic force of the plurality of electromagnets 35, wherein the support portion 11 is the magnetic bearing 30.

[0016] The bearing system of the fifth aspect of this disclosure is a bearing system of any one of the first to third aspects, comprising a bearingless motor 90, which has a support winding 95 that generates an electromagnetic force for supporting the shaft 20 in a non-contact manner by means of energization and a drive winding 96 that generates an electromagnetic force for driving the shaft 20 to rotate by means of energization, wherein the support portion 11 is the bearingless motor 90.

[0017] The sixth aspect of this disclosure is a turbine compressor having a bearing system of any one of the first to fifth aspects.

[0018] The seventh method disclosed herein is a refrigeration system with a turbo compressor having the sixth method.

[0019] The eighth aspect of this disclosure relates to a method for detecting anomalies in a bearing system, the bearing system comprising: a shaft 20; a support portion 11 that supports the shaft 20 in a non-contact manner using electromagnetic force; a bottom bearing 50 that supports the shaft 20 by contact with the shaft 20 when the support portion 11 does not support the shaft 20 in a non-contact manner; and a displacement sensor 70 disposed around the shaft 20 and outputting a signal whose amplitude varies according to the distance between the displacement sensor 70 and the shaft 20. The method for detecting anomalies in this bearing system comprises: a first step of controlling the support portion 11 such that the shaft 20 moves circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50; and a second step of outputting first information indicating an anomaly when the waveform representing a change in data value does not have linear symmetry, wherein the data value varies according to the amplitude change of the signal output from the displacement sensor 70 during the first step.

[0020] In the eighth method, if the waveform representing the change in data value as a result of the amplitude change of the signal output from the displacement sensor 70 during the first action does not have linear symmetry, the output of the first information can notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0021] In the ninth aspect of the present disclosure, in the abnormality detection method of the bearing system of the eighth aspect, the bearing system includes a first displacement sensor 70a and a second displacement sensor 70b, which are disposed around the shaft 20 and output signals whose amplitude varies according to the distance between them and the shaft 20. The position of the second displacement sensor 70b in the circumferential direction is different from the position of the first displacement sensor 70a in the circumferential direction. The displacement sensor 70 is either the first displacement sensor 70a or the second displacement sensor 70b. In the second step, if the waveform representing the change of the first data value or the waveform representing the change of the second data value does not have the line symmetry, the first information is output, wherein the first data value changes according to the amplitude change of the signal output from the first displacement sensor 70a during the first step, and the second data value changes according to the amplitude change of the signal output from the second displacement sensor 70b during the first step.

[0022] In the ninth method, even if line symmetry appears in the waveform representing the change in data value corresponding to one of the first displacement sensor 70a and the second displacement sensor 70b, the waveform representing the change in data value corresponding to the other of the first displacement sensor 70a and the second displacement sensor 70b no longer has linearity. Therefore, by monitoring the waveform representing the change in the first data value and the waveform representing the change in the second data value, it is possible to notify with high precision that an anomaly (specifically, abnormal contact) has occurred in the bearing system 10. Attached Figure Description

[0023] Figure 1 This is a longitudinal sectional view illustrating the structure of a turbo compressor according to an exemplary embodiment.

[0024] Figure 2 This is a cross-sectional view illustrating the structure of a radial magnetic bearing.

[0025] Figure 3 This is a longitudinal sectional view illustrating the structure of a thrust magnetic bearing.

[0026] Figure 4 This is a cross-sectional view illustrating the structure of a bottom-contact bearing.

[0027] Figure 5 This is a longitudinal sectional view illustrating normal contact in a bearing system.

[0028] Figure 6 This is a longitudinal sectional view illustrating an abnormal contact in a bearing system.

[0029] Figure 7 This is a schematic diagram illustrating the configuration of the displacement sensor and the movement of the shaft via the first action during normal contact.

[0030] Figure 8 It is a diagram used to illustrate the amplitude change of the radial displacement sensor signal and the trajectory of the shaft during normal contact.

[0031] Figure 9 This is a schematic diagram illustrating the configuration of the displacement sensor and the movement of the shaft via the first action in the event of abnormal contact.

[0032] Figure 10 It is a diagram used to illustrate the amplitude change of the radial displacement sensor signal and the trajectory of the shaft during abnormal contact.

[0033] Figure 11 This is a cross-sectional view illustrating the structure of a bearingless motor.

[0034] Figure 12 This is a schematic diagram illustrating the structure of a refrigeration system. Detailed Implementation

[0035] The embodiments will now be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings are labeled with the same reference numerals and their descriptions are omitted. Moreover, this disclosure is not limited to the embodiments shown below, and various modifications can be made without departing from the technical concept of this disclosure. The accompanying drawings are for illustrative purposes; therefore, for ease of understanding, dimensions, ratios, or quantities are sometimes exaggerated or simplified as needed.

[0036] (Implementation Method)

[0037] Figure 1 The structure of a turbo compressor 1 according to an exemplary embodiment is shown. The turbo compressor 1 draws in fluid and compresses it, then discharges the compressed fluid. In this example, the turbo compressor 1 includes a housing 2, an impeller 3, and a bearing system 10. The bearing system 10 includes a shaft 20, a first radial magnetic bearing 30a, a second radial magnetic bearing 30b, a first thrust magnetic bearing 40a, a second thrust magnetic bearing 40b, a first bottom-contact bearing 50a, a second bottom-contact bearing 50b, and a motor 60.

[0038] Hereinafter, the first radial magnetic bearing 30a and the second radial magnetic bearing 30b are collectively referred to as "radial magnetic bearing 30", the first thrust magnetic bearing 40a and the second thrust magnetic bearing 40b are collectively referred to as "thrust magnetic bearing 40", and the first bottoming bearing 50a and the second bottoming bearing 50b are collectively referred to as "bottoming bearing 50".

[0039] Furthermore, in the following description, the direction of the axis of a component is referred to as the "axial direction" of that component. The direction orthogonal to the axis of the component is referred to as the "radial direction" of that component. The direction about the axis of the component is referred to as the "circumferential direction" of that component. For example, the axial direction of shaft 20 is the direction of the axis of rotation of shaft 20. The radial direction of shaft 20 is the direction orthogonal to the axis of rotation of shaft 20. The circumferential direction of shaft 20 is the direction about the axis of rotation of shaft 20. Furthermore, for ease of explanation, the statements related to "front," "rear," "left," "right," "up," and "down" below are based on the direction of the turbine compressor 1 as viewed from the front side (impeller 3 side) in its set state.

[0040] 〔chassis〕

[0041] The housing 2 is formed as a cylinder closed at both ends. The space inside the housing 2 is divided into two spaces by the wall 2a: one space constitutes the impeller chamber S1, and the other space constitutes the motor chamber S2. The impeller 3 is housed in the impeller chamber S1. The radial magnetic bearing 30, the thrust magnetic bearing 40, the bottom contact bearing 50, and the motor 60 are housed in the motor chamber S2, and they are fixed to the inner peripheral wall of the motor chamber S2. In this example, the housing 2 is configured such that the axis of the housing 2 (cylindrical axis) is horizontal.

[0042] 〔axis〕

[0043] The shaft 20 is housed within the housing 2. The shaft 20 extends from the impeller chamber S1 through the wall 2a to the motor chamber S2. An impeller 3 is fixed to one end of the shaft 20. For example, the shaft 20 is made of a magnetic material such as iron.

[0044] In this example, the shaft 20 has a recess 21. The recess 21 is located near the other end of the shaft 20. The recess 21 is formed over the entire circumference of the shaft 20. Furthermore, in this example, a first bottom-contact bearing 50a, a first thrust magnetic bearing 40a, a first radial magnetic bearing 30a, a motor 60, a second radial magnetic bearing 30b, a second thrust magnetic bearing 40b, and a second bottom-contact bearing 50b are arranged sequentially from one end of the shaft 20 toward the other end.

[0045] 〔impeller〕

[0046] The impeller 3 has multiple blades and is generally conical in shape. The impeller 3 is housed in the impeller chamber S1, fixed to one end of the shaft 20. An intake pipe P1 and an exhaust pipe P2 are connected to the impeller chamber S1. The intake pipe P1 is provided to guide fluid from the outside into the impeller chamber S1. The exhaust pipe P2 is provided to guide the high-pressure fluid, compressed within the impeller chamber S1, to the outside. In this example, the impeller 3 and the impeller chamber S1 constitute a compression mechanism.

[0047] [Radial magnetic bearing]

[0048] The first radial magnetic bearing 30a and the second radial magnetic bearing 30b have the same structure. The radial magnetic bearing 30 uses electromagnetic force to control the radial position of the shaft 20 in a non-contact manner.

[0049] like Figure 1 and Figure 2 As shown, in this example, the radial magnetic bearing 30 has a stator 31 and a rotor 32. The stator 31 is formed in a cylindrical shape and is fixed to the inner peripheral wall of the housing 2. The rotor 32 is formed in a cylindrical shape and is fixed to the shaft 20. The rotor 32 is arranged inside the stator 31 in such a way that it is opposed to the stator 41 in the radial direction of the shaft 20 by a predetermined gap.

[0050] like Figure 2 As shown, the stator 31 has a stator core 310 and multiple coils 315. The stator core 310 is made of magnetic material and is formed in a cylindrical shape. The stator core 310 has a cylindrical back yoke 311 and multiple teeth 312 disposed on the inner circumferential surface of the back yoke 311. The multiple coils 315 are wound around the multiple teeth 312. By winding the coils 315 on the teeth 312, a radial electromagnet 35 is formed.

[0051] In this example, the radial magnetic bearing 30 has a first radial electromagnet 35a, a second radial electromagnet 35b, a third radial electromagnet 35c, and a fourth radial electromagnet 35d. The first radial electromagnet 35a and the second radial electromagnet 35b are positioned opposite each other across the shaft 20. The third radial electromagnet 35c and the fourth radial electromagnet 35d are positioned opposite each other across the shaft 20. The opposing directions of the third radial electromagnet 35c and the fourth radial electromagnet 35d are orthogonal to the opposing directions of the first radial electromagnet 35a and the second radial electromagnet 35b.

[0052] By energizing the coils 315 of the first radial electromagnet 35a, the second radial electromagnet 35b, the third radial electromagnet 35c, and the fourth radial electromagnet 35d, an electromagnetic force is generated to support the shaft 20 in a non-contact manner in the radial direction of the radial magnetic bearing 30. Furthermore, by controlling the current flowing in the coils 315 of the first and second radial electromagnets 35a and 35b, the position of the shaft 20 in the opposing direction of the first and second radial electromagnets 35a and 35b is controlled. Additionally, by controlling the current flowing in the coils 315 of the third and fourth radial electromagnets 35c and 35d, the position of the shaft 20 in the opposing direction of the third and fourth radial electromagnets 35d is controlled.

[0053] It should be noted that in this example, the opposing directions of the first radial electromagnet 35a and the second radial electromagnet 35b are vertical, and the opposing directions of the third radial electromagnet 35c and the fourth radial electromagnet 35d are horizontal.

[0054] Furthermore, the radial magnetic bearing 30 has a plurality of radial electromagnets 35 disposed around the shaft 20, and the shaft 20 is supported in a non-contact manner by means of the electromagnetic force of the plurality of radial electromagnets 35. The radial magnetic bearing 30 functions as a support portion 11 that supports the shaft 20 in a non-contact manner by means of electromagnetic force. The radial magnetic bearing 30 is an example of the support portion 11.

[0055] [Thrust magnetic bearing]

[0056] The first thrust magnetic bearing 40a and the second thrust magnetic bearing 40b have the same structure. The thrust magnetic bearing 40 uses electromagnetic force to control the axial position of the shaft 20 in a non-contact manner.

[0057] like Figure 1 and Figure 3 As shown, in this example, the thrust magnetic bearing 40 has a stator 41 and a rotor 42. The stator 41 is formed in an annular shape and is fixed to the inner peripheral wall of the housing 2. The rotor 42 is formed in an annular shape and is fixed to the shaft 20. The rotor 42 is configured to be opposed to the stator 41 in the axial direction of the shaft 20 at a predetermined gap.

[0058] like Figure 3 As shown, the stator 41 has a stator core 411 formed in a circular ring shape and a coil 415 wound in a circular ring shape. A circular groove 412 is formed in the stator core 411, and the coil 415 is housed in the groove 412 of the stator core 411. The coil 415 wound in a circular ring shape and housed in the circular groove 412 constitutes a thrust electromagnet 45.

[0059] By energizing the coil 415 of the thrust electromagnet 45 of the thrust magnetic bearing 40, an electromagnetic force is generated to support the shaft 20 in the axial direction of the thrust magnetic bearing 40 in a non-contact manner. Furthermore, the position of the shaft 20 in the axial direction of the thrust magnetic bearing 40 is controlled by controlling the current flowing in the coil 415 of the thrust electromagnet 45 of the thrust magnetic bearing 40.

[0060] [Bottom-out bearing]

[0061] The first bottom-contact bearing 50a and the second bottom-contact bearing 50b have the same structure. The bottom-contact bearing 50 supports the shaft 20 by contacting it when the support portion 11 does not support the shaft 20 in a non-contact manner.

[0062] like Figure 1 and Figure 4 As shown, the bottom bearing 50 is formed in an annular shape. A shaft 20 is inserted through the bottom bearing 50.

[0063] <First bottoming bearing>

[0064] The first bottom-contact bearing 50a is disposed between one end of the shaft 20 (the end where the impeller 3 is fixed) and the first radial magnetic bearing 30a, and is provided in the wall 2a of the housing 2. In this example, the first bottom-contact bearing 50a constitutes a radial bottom-contact bearing.

[0065] Specifically, the first bottom bearing 50a supports the shaft 20 by contacting the shaft 20, which moves radially along the first bottom bearing 50a, with its inner circumferential surface in contact. Furthermore, the contact between the shaft 20 and the inner circumferential surface of the first bottom bearing 50a prevents contact between the stator 61 and rotor 62 of the motor 60 (described later) and contact between the stator 31 and rotor 32 of the radial magnetic bearing 30.

[0066] <Second bottom bearing>

[0067] The second bottom-contact bearing 50b is configured to face the recess 21 of the shaft 20. Specifically, the inner circumferential surface of the second bottom-contact bearing 50b faces the bottom surface of the recess 21 of the shaft 20, and the two axial end faces of the second bottom-contact bearing 50b face the two side faces of the recess 21 of the shaft 20. In this example, the second bottom-contact bearing 50b constitutes a radial thrust bottom-contact bearing.

[0068] Specifically, the second bottom bearing 50b supports the shaft 20 by contacting the bottom surface of the recess 21 of the shaft 20, which moves radially along the second bottom bearing 50b. Furthermore, the contact between the bottom surface of the recess 21 of the shaft 20 and the inner circumferential surface of the second bottom bearing 50b prevents contact between the stator 61 and rotor 62 of the motor 60 (described later) and contact between the stator 31 and rotor 32 of the radial magnetic bearing 30.

[0069] Furthermore, the second bottom bearing 50b supports the shaft 20 by contacting the side of the recess 21 of the shaft 20, which moves axially along the second bottom bearing 50b. Moreover, the contact between the side of the recess 21 of the shaft 20 and the second bottom bearing 50b prevents contact between the stator 41 and the rotor 42 of the thrust magnetic bearing 40.

[0070] [Electric motor]

[0071] The motor 60 drives the shaft 20 to rotate. In this example, the motor 60 has a stator 61 and a rotor 62. The stator 61 is formed in a cylindrical shape and fixed inside the housing 2. The rotor 62 is fixed to the shaft 20 in a coaxial manner. The rotor 62 is arranged inside the stator 61 such that its outer circumferential surface is opposed to the inner circumferential surface of the stator 61 with a predetermined gap.

[0072] [Various sensors]

[0073] Furthermore, various sensors for detecting various physical quantities are installed in the turbo compressor 1 and the bearing system 10. The various information obtained from these sensors is sent to the control unit 80, which will be described later.

[0074] like Figure 1 As shown, the bearing system 10 is equipped with a plurality of radial displacement sensors 70 and thrust displacement sensors 75. The plurality of radial displacement sensors 70 are arranged around the shaft 20. The plurality of radial displacement sensors 70 output signals corresponding to the radial position of the shaft 20. The thrust displacement sensors 75 output signals corresponding to the axial position of the shaft 20. The radial displacement sensors 70 and the thrust displacement sensors 75 will be described in detail later.

[0075] In addition, although the illustration is omitted, the bearing system 10 is equipped with a current sensor that detects the current flowing in the coil 315 of the stator 31 of the radial magnetic bearing 30, a current sensor that detects the current flowing in the coil 415 of the stator 41 of the thrust magnetic bearing 40, a current sensor that detects the current flowing in the coil of the stator 61 of the motor 60, a rotation angle sensor that detects the rotation angle of the shaft 20, and a speed sensor that detects the rotational speed of the shaft 20.

[0076] Furthermore, the various sensors mentioned above can be sensors designed to directly detect the physical quantities described above, or sensors designed to indirectly detect or estimate the physical quantities described above.

[0077] [Storage Department]

[0078] Furthermore, the bearing system 10 includes a storage unit 85. The storage unit 85 stores various information and data. For example, the storage unit 85 stores information and data (such as threshold values ​​or other set values) used to control the bearing system 10 and the turbine compressor 1, as well as information and data (such as measured values) obtained from various sensors installed in the bearing system 10 and the turbine compressor 1.

[0079] [Control Department]

[0080] Furthermore, the bearing system 10 includes a control unit 80. The control unit 80 is connected to various sensors installed in the bearing system 10 and the turbo compressor 1 via signal lines, and receives signals output from the various sensors. The control unit 80 is also connected to the components of the bearing system 10 and the turbo compressor 1 via signal lines, and controls these components.

[0081] The control unit 80 performs various processes. Specifically, the control unit 80 obtains information and data from various parts of the bearing system 10 and the turbo compressor 1, and performs various processes based on this information and data. The processes of the control unit 80 will be described in detail later.

[0082] For example, the control unit 80 is composed of a computer (microcomputer) including a processor, memory, input / output interfaces, etc. The memory is electrically connected to the processor and stores programs and data used to operate the processor. By executing the programs by the processor, various functions of the control unit 80 are realized.

[0083] Furthermore, the control unit 80 includes components for control (such as electrical circuits, electronic circuits, etc.). For example, the control unit 80 includes a power supply unit that supplies power (current or voltage) according to instructions from the processor.

[0084] [Reference position of the shaft]

[0085] Next, the reference position of the shaft 20, which is supported in a non-contact manner, will be explained. When the turbo compressor 1 is started and during operation, the control unit 80 controls the support unit 11 in a manner that makes the position of the shaft 20 a predetermined reference position.

[0086] In this example, the reference position is the position of shaft 20 when its rotation axis coincides with a predetermined "reference axis" and its axial position is at a predetermined "reference axial position". For example, the reference axis is set as the axis of stator 31 of motor 60. The reference axial position is set as the axial position of shaft 20 when the "distance between stator 41 and rotor 42 of first thrust magnetic bearing 40a" and the "distance between stator 41 and rotor 42 of second thrust magnetic bearing 40b" are equal to each other.

[0087] [Ideal settings for each component of the bearing system]

[0088] Next, the ideal settings for each part of the bearing system 10 will be explained. The ideal settings (such as dimensional settings) for each part of the bearing system 10 are as follows.

[0089] The radial magnetic bearing 30 is configured such that its axis coincides with a reference axis (e.g., the axis of the stator 61 of the motor 60). The bottom bearing 50 is configured such that its axis coincides with the reference axis. The inner diameter of the bottom bearing 50 is smaller than the inner diameter of the stator 31 of the radial magnetic bearing 30 (the diameter of the imaginary cylindrical surface tangent to the end of the tooth 312). The distance (radial distance) between various sensors, such as the radial displacement sensor 70, and the reference axis is longer than the inner diameter of the bottom bearing 50.

[0090] With the position of shaft 20 as the reference position, the gap between the first bottom bearing 50a and shaft 20 is narrower than the gaps between the stator 31 and rotor 32 of the radial magnetic bearing 30 and between the stator 61 and rotor 62 of the motor 60.

[0091] With the position of shaft 20 as the reference position, the gap between the second bottom bearing 50b and the bottom surface of the recess 21 of shaft 20 is narrower than the gaps between the stator 31 and rotor 32 of radial magnetic bearing 30 and between the stator 61 and rotor 62 of motor 60.

[0092] Furthermore, with the position of shaft 20 as the reference position, the clearance between the second bottom bearing 50b and one side of the recess 21 of shaft 20 is narrower than the clearance between the stator 41 and rotor 42 of the first thrust magnetic bearing 40a. The clearance between the second bottom bearing 50b and the other side of the recess 21 of shaft 20 is narrower than the clearance between the stator 41 and rotor 42 of the second thrust magnetic bearing 40b.

[0093] [Normal contact and abnormal contact]

[0094] Next, the "normal contact" and "abnormal contact" in the bearing system 10 will be explained. Hereinafter, the "shaft 20" and the "elements that rotate together with the shaft 20" will be referred to as the "rotating body". Examples of elements that rotate together with the shaft 20 include the impeller 3, the rotor 32 of the radial magnetic bearing 30, the rotor 42 of the thrust magnetic bearing 40, and the rotor 62 of the motor 60.

[0095] <Normal contact>

[0096] Normal contact refers to the contact between the bottom bearing 50 and the shaft 20 before the rotating body contacts other components that are not the bottom bearing 50, thereby preventing the contact between the other components and the rotating body.

[0097] Examples of other components that are not bottom-contact bearing 50 include housing 2, stator 31 of radial magnetic bearing 30, stator 41 of thrust magnetic bearing 40, stator 61 of motor 60, radial displacement sensor 70, thrust displacement sensor 75, etc.

[0098] like Figure 5 As shown, when the settings of each part of the bearing system 10 are the aforementioned "ideal settings," normal contact occurs in the bearing system 10. Therefore, unintended contact in the bearing system 10 can be avoided. Unintended contact in the bearing system 10 refers to unintended contact between the rotating body and other components that are not in contact with the bottom bearing 50.

[0099] Examples of unintended contacts in the bearing system 10 include the contact between the stator 61 and rotor 62 of the motor 60, the contact between the stator 31 and rotor 32 of the radial magnetic bearing 30, the contact between the impeller 3 and housing 2, and the contact between the shaft 20 and radial displacement sensor 70.

[0100] <Abnormal Contact>

[0101] Abnormal contact is an abnormal contact in which at least a portion of the rotating body (the shaft 20 and at least one of the elements rotating with the shaft 20) comes into contact with other parts that are not the bottom bearing 50 before the shaft 20 contacts the bottom bearing 50. Examples of causes for such abnormal contact include dimensional deviations of the constituent parts and assembly errors.

[0102] For example, such as Figure 6 As shown, when the axis of the second radial magnetic bearing 30b is set below the reference axis, the axis of the second radial magnetic bearing 30b is not aligned with the axis of the bottom bearing 50. As a result, when the shaft 20 moves upward, abnormal contact occurs, such as the stator 31 of the second radial magnetic bearing 30b contacting the rotor 32.

[0103] [Displacement sensor]

[0104] Next, the radial displacement sensor 70 will be described. The radial displacement sensor 70 is an example of a displacement sensor whose output amplitude varies according to the distance between the radial displacement sensor 70 and the shaft 20.

[0105] In this example, the radial displacement sensor 70 is a gap sensor that outputs a signal corresponding to the distance between the gap sensor and the object being measured. The longer the distance between the gap sensor and the object being measured, the higher the level (amplitude value) of the signal output from the gap sensor.

[0106] Furthermore, in this example, four radial displacement sensors 70 are provided for one radial magnetic bearing 30. Specifically, as... Figure 7 As shown, a first radial displacement sensor 71, a second radial displacement sensor 72, a third radial displacement sensor 73, and a fourth radial displacement sensor 74 are arranged around the axis 20. These radial displacement sensors 70 are configured to face the reference axis R.

[0107] In addition, the first radial displacement sensor 71, the second radial displacement sensor 72, the third radial displacement sensor 73 and the fourth radial displacement sensor 74 correspond to the first radial electromagnet 35a, the second radial electromagnet 35b, the third radial electromagnet 35c and the fourth radial electromagnet 35d of the radial magnetic bearing 30, respectively.

[0108] The first radial displacement sensor 71 and the second radial displacement sensor 72 are positioned opposite each other across shaft 20. The third radial displacement sensor 73 and the fourth radial displacement sensor 74 are also positioned opposite each other across shaft 20. The opposing directions of the third radial displacement sensor 73 and the fourth radial displacement sensor 74 are orthogonal to the opposing directions of the first radial displacement sensor 71 and the second radial displacement sensor 72. In this example, the opposing direction of the first radial displacement sensor 71 and the second radial displacement sensor 72 is vertical, and the opposing direction of the third radial displacement sensor 73 and the fourth radial displacement sensor 74 is horizontal.

[0109] The first radial displacement sensor 71 and the second radial displacement sensor 72 output signals corresponding to the position of the shaft 20 in the opposing direction of the first radial electromagnet 35a and the second radial electromagnet 35b of the radial magnetic bearing 30. The third radial displacement sensor 73 and the fourth radial displacement sensor 74 output signals corresponding to the position of the shaft 20 in the opposing direction of the third radial electromagnet 35c and the fourth radial electromagnet 35d of the radial magnetic bearing 30.

[0110] Alternatively, the structure of the thrust displacement sensor 75 can be the same as that of the radial displacement sensor 70. For example, the thrust displacement sensor 75 can also be a gap sensor. In this example, the thrust displacement sensor 75 is configured to be positioned axially opposite the rotor 42 of the second thrust magnetic bearing 40b at a predetermined interval from the shaft 20, and outputs a signal corresponding to the distance between the thrust displacement sensor 75 and the rotor 42 of the second thrust magnetic bearing 40b.

[0111] [Handling by the Control Department]

[0112] Next, the processing of the control unit 80 will be explained. The control unit 80 performs various processes, including hover position control and inspection processing.

[0113] [Hover position control]

[0114] Suspension position control is a process used to control the position of the shaft 20, which is supported by the support 11 in a non-contact manner. When the support 11 supports the shaft 20 in a non-contact manner, the control unit 80 performs suspension position control. In suspension position control, the control unit 80 detects the position of the shaft 20 based on signals output from multiple radial displacement sensors 70 and thrust displacement sensors 75, and controls the support 11 so that the position of the shaft 20 is a predetermined reference position.

[0115] Specifically, the control unit 80 detects the radial position (position of the rotation axis) of the shaft 20 based on signals output from multiple radial displacement sensors 70, and controls the current flowing in the coil 315 of the stator 31 of the radial magnetic bearing 30 so that the radial position of the shaft 20 becomes a predetermined reference radial position (position of the reference axis). Furthermore, the control unit 80 detects the axial position of the shaft 20 based on signals output from the thrust displacement sensor 75, and controls the current flowing in the coil 415 of the stator 41 of the thrust magnetic bearing 40 so that the axial position of the shaft 20 becomes a predetermined reference axial position.

[0116] By repeatedly performing the above process, the position of shaft 20 is maintained at the reference position.

[0117] [Inspection and Handling]

[0118] The inspection process is used to check for any abnormal contact. For example, when a check instruction to start the inspection process is received, the control unit 80 executes the inspection process. It should be noted that the inspection process can be performed before or after the turbo compressor 1 leaves the factory. During the inspection process, the control unit 80 performs a first action and a second action.

[0119] Furthermore, the inspection and processing of the control unit 80 is an example of the abnormality detection method of the bearing system 10. The first action and the second action are examples of the first and second steps in the abnormality detection method of the bearing system 10.

[0120] In the first operation, the control unit 80 controls the support unit 11, causing the shaft 20 to move circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50. In the second operation, if the amplitude change of the signal output from at least one of the plurality of radial displacement sensors 70 during the first operation is not the amplitude change that occurs when the shaft 20 moves circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, the control unit 80 outputs a first message indicating an anomaly.

[0121] Furthermore, in this example, the amplitude change of the signal output from the radial displacement sensor 70 is the change in the signal amplitude relative to the positional change of the shaft 20 in the circumferential direction of the bottom bearing 50. Moreover, in the second operation, if the waveform representing the amplitude change of the signal output from at least one of the plurality of radial displacement sensors 70 during the first operation does not exhibit the linear symmetry characteristic of the shaft 20 moving circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, the control unit 80 outputs first information.

[0122] Furthermore, in this example, the control unit 80 monitors the signals output from two or more radial displacement sensors 70 in the second operation. Specifically, the control unit 80 monitors the signals output from two or more radial displacement sensors 70 in the second operation, wherein the two or more radial displacement sensors 70 include two radial displacement sensors 70 that are not radially opposed to each other in the radial direction of the radial magnetic bearing 30 (e.g., a first radial displacement sensor 71 and a third radial displacement sensor 73).

[0123] [Details of the first action]

[0124] Next, refer to Figure 7 The first action will be described in detail. In addition, the direction of movement of axis 20 in the first action is described as "clockwise" and the angle of clockwise direction from "the reference line extending vertically downward from the reference axis R" to "the line extending from the reference axis R to the position of axis 20 (specifically, the position of axis Q of axis 20)" will be described as "rotational position angle θ".

[0125] At the start of the first operation, both the support 11 and the drive 12 are at rest. Therefore, the shaft 20 is located at the lowest point of the inner circumferential surface of the bottom bearing 50 (the point where it intersects with the reference line extending vertically downward from the reference axis R) due to gravity. The control unit 80 activates the support 11 and controls it to gradually increase the rotational position angle θ of the shaft 20. As a result, the shaft 20 gradually moves clockwise in the circumferential direction of the bottom bearing 50.

[0126] Furthermore, the position (rotational position angle θ) of shaft 20 is related to the direction of the electromagnetic force acting on shaft 20 (in this example, the combined electromagnetic force of the multiple radial electromagnets 35 of radial magnetic bearing 30). Specifically, shaft 20 is pressed against the inner circumferential surface of bottom bearing 50 in the direction of the "combined electromagnetic force acting on shaft 20," therefore, it can be deduced that, viewed from the reference axis R, the position of shaft 20 is in the direction of the "combined electromagnetic force acting on shaft 20." This deduction (derived) of the position of shaft 20 is performed by control unit 80.

[0127] Furthermore, the direction of the combined electromagnetic force acting on shaft 20 is related to the direction and magnitude of the current flowing through each of the multiple radial electromagnets 35. Therefore, by controlling the direction and magnitude of the current flowing through each of the multiple radial electromagnets 35, the position (rotational position angle θ) of shaft 20 can be moved to the desired position. Such control is performed by control unit 80.

[0128] Thus, the first action performed by the control unit 80 continues, and the shaft 20 continues to move clockwise in the circumferential direction at the bottom bearing 50.

[0129] [The relationship between the presence or absence of abnormal contact and changes in signal amplitude]

[0130] Next, refer to Figures 7-10 The relationship between "the presence or absence of abnormal contact" and "the amplitude change of the signal output from the radial displacement sensor 70" is explained. Figure 7 and Figure 8 Examples of normal contact occurring without any abnormal contact are examples of situations where abnormal contact occurs. Figure 9 and Figure 10 The example is an instance of an abnormal contact.

[0131] Furthermore, the position where the distance between the axis 20 and the axis 20 is minimized when the rotational position angle θ is "0°" will be referred to as the "0° position". The same applies to the designations "90° position", "180° position", and "270° position". In this example, the first radial displacement sensor 71 is positioned at the "0° position", the second radial displacement sensor 72 is positioned at the "180° position", the third radial displacement sensor 73 is positioned at the "90° position", and the fourth radial displacement sensor 74 is positioned at the "270° position".

[0132] like Figure 7 and Figure 8 As shown, in the absence of abnormal contact, during the first action, the increase and decrease of the distance between the shaft 20 and the radial displacement sensor 70 are symmetrical. As a result, the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 includes a waveform portion that has a shape representing "linear symmetry corresponding to the increase or decrease of the symmetry of the distance between the shaft 20 and the radial displacement sensor 70".

[0133] For example, in the first action, the distance between the shaft 20 and the first radial displacement sensor 71 gradually increases as the rotational position angle θ of the shaft 20 gradually increases from "0°" to "180°", reaches its maximum value when the rotational position angle θ of the shaft 20 is "180°", and then gradually decreases as the rotational position angle θ of the shaft 20 gradually increases from "180°" to "360°".

[0134] The result is, as Figure 8As shown, in the first operation, the amplitude of the signal output from the first radial displacement sensor 71 increases or decreases in the same way as the symmetry of the distance between the shaft 20 and the first radial displacement sensor 71. Furthermore, the waveform of the signal amplitude during the period when the rotational position angle θ of the shaft 20 ranges from 180° to 360° is linearly symmetrical with respect to the waveform of the signal amplitude during the period when the rotational position angle θ of the shaft 20 ranges from 0° to 180° (linear symmetry about the line of 180°). In other words, in the absence of abnormal contact, the waveform representing the change in the amplitude of the signal output from the first radial displacement sensor 71 includes a portion of the waveform that can be represented by an even function. Similarly, the second radial displacement sensor 72, the third radial displacement sensor 73, and the fourth radial displacement sensor 74 can also be said to be the same as the first radial displacement sensor 71.

[0135] Furthermore, the aforementioned "even function" satisfies f （X0+X） =f （X0-X） The function. In the XY plane with the X-axis as the horizontal axis and the Y-axis as the vertical axis, the even function is linearly symmetric about the straight line passing through "X0" (the straight line X=X0). The waveform representing the change in amplitude of the signal output from the radial displacement sensor 70 can be represented by a function in the XY plane with "rotational position angle θ of axis 20" as the X-axis (horizontal axis) and "signal amplitude" as the Y-axis (vertical axis). When the above waveform includes a portion that can be represented by an even function, the function representing the above waveform contains a specified rotational position angle θ corresponding to "X0" (the value of the axis of symmetry of the even function) in the even function.

[0136] Furthermore, the aforementioned linear symmetry is independent of installation errors and individual variations in the radial displacement sensor 70. In other words, even if there are installation errors or individual variations in the radial displacement sensor 70, as long as no abnormal contact occurs in the bearing system 10, the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 will exhibit the aforementioned linear symmetry.

[0137] On the other hand, such as Figure 9 as well as Figure 10 As shown, when the symmetry of the increase and decrease in the distance between shaft 20 and radial displacement sensor 70 is disrupted due to abnormal contact, the waveform representing the amplitude change of the signal output from radial displacement sensor 70 does not have the aforementioned "linear symmetry".

[0138] exist Figure 9In the example, during the period when the rotational position angle θ of shaft 20 increases from "180°" to "270°", an abnormal contact occurs where an obstacle 55, which is not a component of the bottom bearing 50, comes into contact with shaft 20. In this case, during the period of this abnormal contact, it is impossible for shaft 20 to move circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, during the period of abnormal contact, the amplitude change of the signal output from the radial displacement sensor 70 becomes a different amplitude change than the amplitude change when shaft 20 moves circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50.

[0139] The result is, as Figure 10 As shown, the change in amplitude of the signal output from the first radial displacement sensor 71 during the period when the rotational position angle θ of shaft 20 increases from "180°" to "270°" does not represent a normal change of slow decrease. Figure 10 The change in the waveform shown by the solid line is not a change that is normal, but a steeper and linear change. Figure 10 (The waveform changes shown by the dashed line). Therefore, the waveform representing the amplitude change of the signal output from the first radial displacement sensor 71 does not have the aforementioned "line symmetry". Furthermore, the same can be said for the second radial displacement sensor 72, the third radial displacement sensor 73, and the fourth radial displacement sensor 74 as for the first radial displacement sensor 71.

[0140] [Details of the second action]

[0141] Next, refer to Figure 8 and Figure 10 The second action will now be described in detail. The control unit 80 monitors the amplitude change of the signal output from at least one of the plurality of radial displacement sensors 70 in parallel with the first action described above. In this example, four signals output from four radial displacement sensors 70 are monitored.

[0142] Furthermore, in the second operation, the control unit 80 determines, for each of the monitored radial displacement sensors 70 (in this example, each of the four radial displacement sensors 70), whether the amplitude change of the signal output from the radial displacement sensor 70 is "the amplitude change when the shaft 20 moves circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50 (hereinafter referred to as "normal change")".

[0143] In this example, the control unit 80 determines whether the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 has "linear symmetry when the shaft 20 moves circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50". If the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 has the aforementioned "linear symmetry", the amplitude change of the signal is a "normal change"; otherwise, the amplitude change of the signal is not a "normal change".

[0144] For example, the control unit 80 detects the inflection point of the waveform representing the amplitude change of the signal output from the radial displacement sensor 70, and derives the similarity of the following two changes: "the amplitude change of the signal when looking back from the time point of the inflection point within a predetermined period before the inflection point" and "the amplitude change of the signal when moving forward from the inflection point within a predetermined period after the inflection point." Furthermore, if the similarity exceeds a predetermined threshold, the control unit 80 determines that the amplitude change of the signal output from the radial displacement sensor 70 has the aforementioned "linear symmetry"; otherwise, it determines that the amplitude change of the signal output from the radial displacement sensor 70 does not have the aforementioned "linear symmetry." In addition, known similarity calculation techniques can be used in deriving the similarity.

[0145] If the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 exhibits "linear symmetry" (meaning the signal amplitude change is "normal"), the control unit 80 does not output first information indicating an anomaly and continues to monitor the signal output from the radial displacement sensor 70. On the other hand, if the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 does not exhibit "linear symmetry" (meaning the signal amplitude change is not "normal"), the control unit 80 outputs first information indicating an anomaly.

[0146] Alternatively, the control unit 80 may output the first information by outputting an image or voice representing the first information. Or, the control unit 80 may output the first information by outputting light or sound corresponding to the first information. For example, the control unit 80 may also output the first information by controlling a notification unit (not shown) that notifies various information. Examples of notification units include a display showing an image representing the information to be notified, a speaker outputting voice representing the information to be notified, a lamp outputting notification light corresponding to the information to be notified, and a buzzer outputting notification sound corresponding to the information to be notified.

[0147] Furthermore, the control unit 80 may also be configured to output second information indicating normal operation when the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 has "line symmetry" (when the amplitude change of the signal is "normal"). The output of the second information may also be the same as the output of the first information.

[0148] [Effects of the Implementation Method]

[0149] As described above, in the bearing system 10 of the embodiment, the control unit 80 performs a first operation and a second operation. In the first operation, the support unit 11 is controlled so that the shaft 20 moves along the circumferential direction of the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50. In the second operation, if the amplitude change of the signal output from at least one of the plurality of displacement sensors 70 during the first operation is not the amplitude change when the shaft 20 moves along the circumferential direction of the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, a first message indicating an abnormality is output.

[0150] In the above structure, if abnormal contact occurs in the bearing system 10, during the period of abnormal contact during the first operation, the shaft 20 cannot move circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, during the period of abnormal contact, the amplitude change of the signal output from the radial displacement sensor 70 becomes a different amplitude change than the amplitude change when the shaft 20 moves circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, by outputting first information when the amplitude change of the signal output from the radial displacement sensor 70 is not the aforementioned amplitude change, it is possible to notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0151] Furthermore, in the bearing system 10 of the embodiment, the amplitude change of the signal output from the radial displacement sensor 70 is the change in the amplitude of the signal relative to the position change of the shaft 20 in the circumferential direction of the bottom bearing 50.

[0152] In the above structure, by monitoring the change in amplitude of the signal (output from the radial displacement sensor 70) relative to the change in the circumferential position of the shaft 20 in the bottom bearing 50, even when the moving speed of the shaft 20 is not constant (when the change in amplitude of the signal relative to the passage of time is not constant), the first information can be output appropriately. Thus, it is possible to appropriately notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0153] Furthermore, in the bearing system 10 of the embodiment, during the second operation, if the waveform representing the amplitude change of the signal output from at least one of the plurality of radial displacement sensors 70 during the first operation does not have the linear symmetry of the shaft 20 moving circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, the control unit 80 outputs first information.

[0154] In the above structure, when no abnormal contact occurs in the bearing system 10, during the first operation, the increase and decrease in the distance between the shaft 20 and the radial displacement sensor 70 are symmetrical. As a result, the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 includes a waveform portion that has a shape representing a linear symmetry corresponding to the increase or decrease in the symmetry of the distance between the shaft 20 and the radial displacement sensor 70. On the other hand, when abnormal contact occurs in the bearing system 10, the symmetry of the increase and decrease in the distance between the shaft 20 and the radial displacement sensor 70 is disrupted. As a result, when the waveform representing the amplitude change of the signal output from the radial displacement sensor 70 does not have the aforementioned linear symmetry, first information is output. Thus, it is possible to notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0155] Furthermore, the aforementioned linear symmetry is independent of the installation error of the radial displacement sensor 70 and individual differences. Therefore, the first information can be output with high accuracy regardless of the installation error or individual differences of the radial displacement sensor 70. As a result, it is possible to notify the bearing system 10 of any abnormality with high precision.

[0156] Furthermore, in the bearing system 10 of the embodiment, the control unit 80 monitors the signals output by two or more radial displacement sensors 70 from a plurality of radial displacement sensors 70 during the second operation.

[0157] In the above structure, by monitoring the signals output from two or more radial displacement sensors 70, the first information can be output with high precision compared to monitoring the signal output from only one radial displacement sensor 70. Therefore, it is possible to accurately notify of an anomaly (specifically, abnormal contact) occurring in the bearing system 10.

[0158] Specifically, in the second operation, the control unit 80 monitors the signals output from two or more radial displacement sensors 70, including two radial displacement sensors 70 that are not opposed to each other in the radial direction of the radial magnetic bearing 30. Furthermore, in the event of abnormal contact in the bearing system 10, line symmetry may appear in the waveform representing the amplitude change of the signal output from the radial displacement sensor 70, which is positioned radially opposite the obstacle 55 to the radial direction of the radial magnetic bearing 30.

[0159] In the above structure, in the event of abnormal contact in the bearing system 10, even if the waveform representing the amplitude change of the signal output from any one of the two or more radial displacement sensors 70 exhibits linear symmetry, the waveform representing the amplitude change of the signal output from the other radial displacement sensors 70 will no longer be linear. Therefore, by monitoring the signals output from each of two or more radial displacement sensors 70, including two radial displacement sensors 70 that are not radially opposed to each other in the radial direction of the radial magnetic bearing 30, it is possible to notify with high precision that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0160] Furthermore, in the bearing system 10 of this embodiment, the control unit 80 can directly monitor the signal output from the displacement sensor 70, or it can indirectly monitor the signal output from the displacement sensor 70 by monitoring the data value that changes according to the amplitude change of the signal output from the displacement sensor 70. In this example, the displacement sensor 70 is a radial displacement sensor 70.

[0161] For example, the data value increases as the amplitude of the signal output from the displacement sensor 70 increases, and decreases as the amplitude of the signal output from the displacement sensor 70 decreases. Alternatively, the data value decreases as the amplitude of the signal output from the displacement sensor 70 increases, and increases as the amplitude of the signal output from the displacement sensor 70 decreases. Examples of data values ​​include data values ​​that directly represent the amplitude of the signal output from the displacement sensor 70, and data values ​​that indirectly represent the amplitude of the signal output from the displacement sensor 70. For example, the data value could also be a data value representing the amplitude of the signal (the signal output from the displacement sensor 70) after processing such as smoothing based on a low-pass filter (illustration omitted).

[0162] Furthermore, in the second operation of the bearing system 10 in the embodiment, the control unit 80 may also output first information indicating an anomaly when the waveform representing the change in data value does not have linear symmetry, wherein the data value changes according to the amplitude change of the signal output from the displacement sensor 70 when the first operation is performed.

[0163] In the above structure, in the absence of abnormal contact in the bearing system 10, the increase and decrease of the distance between the shaft 20 and the displacement sensor 70 in the first action are symmetrical. As a result, the waveform representing the change of data value has linear symmetry, wherein the data value changes according to the amplitude of the signal output from the displacement sensor 70.

[0164] On the other hand, in the event of abnormal contact in the bearing system 10, during the period of abnormal contact during the first operation, the shaft 20 cannot move circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Thus, when abnormal contact occurs in the bearing system 10, the symmetry of the increase and decrease in the distance between the shaft 20 and the displacement sensor 70 is disrupted, resulting in the waveform representing the amplitude change of the signal output from the displacement sensor 70 lacking linear symmetry.

[0165] Therefore, when the waveform representing the change in data value does not have linear symmetry, first information is output, thereby notifying that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10, wherein the data value changes according to the amplitude change of the signal output from the displacement sensor 70 when the first action is performed.

[0166] Furthermore, the bearing system 10 in the embodiment may also include a first displacement sensor 70a and a second displacement sensor 70b. The displacement sensor 70 may be either the first displacement sensor 70a or the second displacement sensor 70b.

[0167] A first displacement sensor 70a and a second displacement sensor 70b are disposed around the shaft 20, and each outputs a signal whose amplitude varies according to the distance from the shaft 20. The circumferential position of the second displacement sensor 70b differs from that of the first displacement sensor 70a. The second displacement sensor 70b is not radially opposed to the first displacement sensor 70a (e.g., radially in the direction of the radial magnetic bearing 30). In this example, the first displacement sensor 70a is either a first radial displacement sensor 71 or a second radial displacement sensor 72. The second displacement sensor 70b is either a third radial displacement sensor 73 or a fourth radial displacement sensor 74.

[0168] Furthermore, in the second operation of the bearing system 10 in the embodiment, the control unit 80 can also monitor the first data value and the second data value. The first data value changes according to the amplitude change of the signal output from the first displacement sensor 70a when the first operation is performed, and the second data value changes according to the amplitude change of the signal output from the second displacement sensor 70b when the first operation is performed.

[0169] In the above structure, by monitoring both the first and second data values, the first information can be output with high precision compared to monitoring only one data value (a data value that changes according to the amplitude variation of the signal output from the displacement sensor 70). Therefore, it is possible to notify with high precision that an anomaly (specifically, abnormal contact) has occurred in the bearing system 10.

[0170] Furthermore, in the second operation of the bearing system 10 in the embodiment, the control unit 80 may output first information if the waveform representing the change of the first data value or the waveform representing the change of the second data value does not have linear symmetry.

[0171] In addition, in the event of abnormal contact in the bearing system 10, line symmetry may appear in the waveform representing the change of data value (data value that changes according to the amplitude of the signal output from the displacement sensor 70) corresponding to the displacement sensor 70, which is positioned in the radial direction (e.g., the radial direction of the radial magnetic bearing 30) opposite the obstacle 55.

[0172] In the above structure, even though line symmetry appears in the waveform representing the change in data value corresponding to one of the first displacement sensor 70a and the second displacement sensor 70b, the waveform representing the change in data value corresponding to the other of the first displacement sensor 70a and the second displacement sensor 70b no longer has linearity. Therefore, by monitoring the waveform representing the change in the first data value and the waveform representing the change in the second data value, it is possible to notify with high precision that an anomaly (specifically, abnormal contact) has occurred in the bearing system 10.

[0173] (Modification 1 of the implementation method)

[0174] In the bearing system 10 of Embodiment Modification 1, the second operation of the control unit 80 differs from that of the bearing system 10 of Embodiment Modification 1. Other structures and processes of the bearing system 10 of Embodiment Modification 1 are the same as those of the bearing system 10 of Embodiment Modification 1.

[0175] In a variation of the embodiment 1, during the second operation, if the trajectory of the shaft 20 is not the trajectory of the shaft 20 moving circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, the control unit 80 outputs first information, wherein the trajectory of the shaft 20 is derived based on the amplitude change of the signals output by two or more of the plurality of radial displacement sensors 70 during the first operation.

[0176] [Details of the second action]

[0177] Next, refer to Figure 8 and Figure 10The second operation of variation 1 of the embodiment will be described in detail. In this example, at least one of the first radial displacement sensor 71 and the second radial displacement sensor 72 that are opposed to each other, and at least one of the third radial displacement sensor 73 and the fourth radial displacement sensor 74 that are opposed to each other in a direction orthogonal to the opposing direction of the first radial displacement sensor 71 and the second radial displacement sensor 72, becomes the monitoring object.

[0178] Hereinafter, the opposing direction of the first radial displacement sensor 71 and the second radial displacement sensor 72 will be referred to as the "X-axis direction", and the opposing direction of the third radial displacement sensor 73 and the fourth radial displacement sensor 74 will be referred to as the "Y-axis direction".

[0179] The control unit 80 detects the "change in position of shaft 20 in the X-axis direction" corresponding to the change in the rotational position angle θ of shaft 20 based on the amplitude change of the signal output from the first radial displacement sensor 71 (or the second radial displacement sensor 72). Similarly, the control unit 80 detects the "change in position of shaft 20 in the Y-axis direction" corresponding to the change in the rotational position angle θ of shaft 20 based on the amplitude change of the signal output from the third radial displacement sensor 73 (or the fourth radial displacement sensor 74).

[0180] Next, the control unit 80 derives the trajectory of the axis 20 on the XY plane (the plane defined by the X-axis direction and the Y-axis direction) based on the "change in position of the axis 20 in the X-axis direction" corresponding to the change in the rotational position angle θ of the axis 20, and the "change in position of the axis 20 in the Y-axis direction" corresponding to the change in the rotational position angle θ of the axis 20. Specifically, the trajectory of the axis Q of the axis 20.

[0181] Next, the control unit 80 determines whether the derived "track of shaft 20" is the "track of shaft 20 moving circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50 (hereinafter referred to as "normal track")". If the derived track of shaft 20 is a "normal track", the amplitude change of the signal used to derive the track of shaft 20 (the signal output from the radial displacement sensor 70) is a "normal change"; otherwise, the amplitude change of the signal is not a "normal change".

[0182] For example, a normal trajectory is a circular shape (specifically, a perfect circle) that forms the inner circumferential surface of the bottom-contact bearing 50. In this case, the control unit 80 outputs the roundness of the trajectory of the shaft 20. If the roundness exceeds a predetermined threshold, the output trajectory of the shaft 20 is determined to be a "normal trajectory"; otherwise, the output trajectory of the shaft 20 is determined not to be a "normal trajectory".

[0183] If the derived trajectory of shaft 20 is a "normal trajectory" (the amplitude change of the signal is a "normal change"), the control unit 80 does not output the first information indicating an abnormality and continues to monitor the signal output from the radial displacement sensor 70. On the other hand, if the derived trajectory of shaft 20 is not a "normal trajectory" (the amplitude change of the signal is not a "normal change"), the control unit 80 outputs the first information indicating an abnormality.

[0184] [Effects of Variation 1 of the Implementation Method]

[0185] In the bearing system 10 of the modified embodiment 1, if abnormal contact occurs in the bearing system 10, during the period of abnormal contact during the first operation, the shaft 20 cannot move circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, during the period of abnormal contact, the trajectory of the shaft 20 becomes a shape different from the trajectory of the shaft 20 moving circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, when the trajectory of the shaft 20 is not the aforementioned trajectory, by outputting the first information, it is possible to notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0186] In addition, in the bearing system 10 of the modified embodiment 1, the control unit 80 may also derive the trajectory of the shaft 20 based on the waveform representing the change of the first data value and the waveform representing the change of the second data value, wherein the first data value changes according to the amplitude change of the signal output from the first displacement sensor 70a, and the second data value changes according to the amplitude change of the signal output from the second displacement sensor 70b.

[0187] Furthermore, in the bearing system 10 of the modified embodiment 1, it is also possible that, during the second operation, if the trajectory of the shaft 20 derived from the first data value and the second data value respectively during the first operation does not have symmetry, the control unit 80 outputs first information. For example, a symmetrical trajectory is a perfect circle. The control unit 80 may also derive the roundness of the trajectory of the shaft 20, and if the derived roundness is below a predetermined threshold, it determines that the trajectory of the shaft 20 has symmetry.

[0188] (Modification 2 of the implementation method)

[0189] The bearing system 10 of the modified embodiment 2 includes Figure 11 The bearingless motor 90 shown is an example. Alternatively, the bearingless motor 90 can be installed in place of the radial magnetic bearing 30 and the motor 60, or it can be installed together with the radial magnetic bearing 30 and the motor 60.

[0190] [Bearingless motor]

[0191] like Figure 11 As shown, the bearingless motor 90 has a rotor 91 and a stator 92. It uses electromagnetic force to support the shaft 20 in a non-contact manner and drives the shaft 20 to rotate. The rotor 91 is fixed to the shaft 20, and the stator 92 is fixed to the inner peripheral wall of the housing 2.

[0192] The bearingless motor 90 has a support winding 95 and a drive winding 96. The support winding 95 and the drive winding 96 are disposed on the stator 92.

[0193] The support winding 95 is a winding that uses energization to generate electromagnetic force for supporting the shaft 20 in a non-contact manner. The support winding 95 functions as a support portion 11 that uses electromagnetic force to support the shaft 20 in a non-contact manner. The support winding 95 is an example of the support portion 11.

[0194] The drive winding 96 is a winding that generates an electromagnetic force for rotating the drive shaft 20 by energizing it. The drive winding 96 functions as a drive unit 12 that drives the shaft 20 to rotate using electromagnetic force. The drive winding 96 is an example of the drive unit 12.

[0195] As described above, the bearingless motor 90 is both an example of the support unit 11 and an example of the drive unit 12. Furthermore, in this example, the bearingless motor 90 is constructed as a consecutive-pole type bearingless motor. The structures of the rotor 91 and stator 92 are as follows.

[0196] <Rotor>

[0197] The rotor 91 has a rotor core 910 and a plurality of permanent magnets 911. The rotor core 910 is made of magnetic material and is formed into a cylindrical shape. For example, the rotor core 910 is composed of a laminated core made of stacked circular electromagnetic steel plates. A shaft hole for inserting a shaft 20 is provided in the center of the rotor core 910. The plurality of permanent magnets 911 are arranged at a predetermined angular spacing in the circumferential direction of the rotor 91.

[0198] In this example, four permanent magnets 911 are provided on the rotor 91. The four permanent magnets 911 are arranged at a 90° angular spacing in the circumferential direction of the rotor 91 and embedded in the outer periphery (near the outer peripheral surface) of the rotor core 910. In addition, the four permanent magnets 911 are formed in an arc shape along the outer peripheral surface of the rotor core 910, with the outer peripheral surface side becoming the N pole.

[0199] With this structure, the portion of the outer periphery of the rotor core 910 located between the four permanent magnets 911 in the circumferential direction of the rotor 91 becomes a simulated S pole. Alternatively, the outer peripheral surfaces of the four permanent magnets 911 can also serve as S poles. In this case, the portion of the outer periphery of the rotor core 910 located between the four permanent magnets 911 in the circumferential direction of the rotor 91 becomes a simulated N pole.

[0200] <stator>

[0201] The stator 92 and rotor 91 are positioned opposite each other with a predetermined air gap. The stator 92 has a stator core 920, a support winding 95, and a drive winding 96. The stator core 920 is made of a magnetic material. For example, the stator core 920 is made of a laminated core of stacked annular electromagnetic steel plates. The stator core 920 has a cylindrical back yoke and multiple teeth (not shown) disposed on the inner circumferential surface of the back yoke.

[0202] The support winding 95 is wound on the radially outer portion of the teeth of the stator core 920. In this example, three types of support windings 95 are provided in the bearingless motor 90. Specifically, in Figure 11 The support winding 95, surrounded by a thick solid line, constitutes the support winding of phase U. In Figure 11 The support winding 95, surrounded by a thick dashed line, constitutes the support winding for phase V. Figure 11 The support winding 95, surrounded by a thin solid line, constitutes the support winding of phase W.

[0203] The drive winding 96 is wound radially inside the teeth of the stator core 920. In this example, three types of drive windings 96 are provided in the bearingless motor 90. Specifically, in Figure 11 The drive winding 96, surrounded by a thick solid line, constitutes the drive winding of phase U. In Figure 11 The drive winding 96, surrounded by a thick dashed line, constitutes the drive winding of phase V. Figure 11 The drive winding 96, surrounded by a thin solid line, constitutes the drive winding of phase W.

[0204] (Refrigeration system)

[0205] Figure 12 The structure of a refrigeration system RR is illustrated. The refrigeration system RR has a refrigerant circuit RR1 filled with refrigerant. The refrigerant circuit RR1 includes a turbo compressor 1, a radiator RR5, a pressure reducing mechanism RR6, and an evaporator RR7. In this example, the pressure reducing mechanism RR6 is an expansion valve. The refrigerant circuit RR1 performs a vapor compression refrigeration cycle.

[0206] In the refrigeration cycle, the refrigerant discharged from the turbo compressor 1 dissipates heat in the radiator RR5. The refrigerant flowing out of the radiator RR5 is depressurized in the pressure reducing mechanism RR6 and evaporates in the evaporator RR7. Then, the refrigerant flowing out of the evaporator RR7 is drawn into the turbo compressor 1.

[0207] In this example, the refrigeration system RR is an air conditioner. The air conditioner can be a dedicated refrigeration unit or a dedicated heating unit. Furthermore, the air conditioner can also be one that switches between cooling and heating. In this case, the air conditioner has a switching mechanism (e.g., a four-way reversing valve) to switch the refrigerant circulation direction. Alternatively, the refrigeration system RR can also be a water heater, a cooling unit, or a cooling device that cools the air inside a storage facility. The cooling device cools the air inside cold storage rooms, freezers, containers, etc.

[0208] (Other implementation methods)

[0209] The above description can also be used to construct or process the material as follows.

[0210] The radial displacement sensor 70 is not limited to an eddy current type gap sensor. For example, the gap sensor can also be an ultrasonic, optical, or other type of gap sensor. Furthermore, the radial displacement sensor 70 can also be other sensors capable of measuring distance in a non-contact manner, such as a laser displacement meter.

[0211] In the second operation, the control unit 80 may also be configured to monitor only the signal output from a radial displacement sensor 70.

[0212] "Normal change" refers to the amplitude change of the signal when the shaft 20 moves circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50. This "normal change" can also be set to a pre-measured normal amplitude change (e.g., the amplitude change measured when no abnormal contact occurs). In this case, the control unit 80 can also calculate the similarity between the "amplitude change of the signal output from the radial displacement sensor 70" and the pre-determined "normal change". If the similarity exceeds a pre-determined threshold, the amplitude change of the signal output from the radial displacement sensor 70 is determined to be a "normal change"; otherwise, the amplitude change of the signal output from the radial displacement sensor 70 is determined not to be a "normal change".

[0213] The opposing directions of the first radial electromagnet 35a and the second radial electromagnet 35b are not limited to the vertical direction, and the opposing directions of the third radial electromagnet 35c and the fourth radial electromagnet 35d are not limited to the horizontal direction. The same applies to the opposing directions of the first radial displacement sensor 71 and the second radial displacement sensor 72 and the third radial displacement sensor 73 and the fourth radial displacement sensor 74.

[0214] For example, the opposing direction of the first radial electromagnet 35a and the second radial electromagnet 35b can also be "from the lower left to the upper right (relative to)". Figure 2The direction of the vertical direction is tilted 45° clockwise. The opposing direction of the third radial electromagnet 35c and the fourth radial electromagnet 35d can also be "from the lower left to the upper right (relative to the direction of the vertical direction)". Figure 2 (The direction of the vertical direction is tilted counterclockwise at 45°).

[0215] The number of radial displacement sensors 70 is not limited to four. The number of radial displacement sensors 70 can be less than four or more than four. The same applies to other components.

[0216] Inspection and processing can also be performed after the turbo compressor 1 is installed. By performing inspection and processing after the turbo compressor 1 is installed, abnormal contacts caused by post-manufacturing abnormalities can be detected. Examples of post-manufacturing abnormalities include vibrations applied to the turbo compressor 1 during transport from the factory to the installation site, deformation caused by piping connections during the installation of the turbo compressor 1, and the slope of the installation site of the turbo compressor 1.

[0217] The movement of shaft 20 in the first operation (movement along the circumference of the bottom bearing 50) can be more than one revolution or less than one revolution. For example, the control unit 80 may control the support unit 11 in the first operation so that shaft 20 moves a predetermined amount (less than one revolution) along the circumference of bottom bearing 50 while contacting the inner circumferential surface of bottom bearing 50. In this case, the control unit 80 may also be configured to repeatedly perform the first operation by rotating shaft 20 one revolution along the circumference of bottom bearing 50, and to perform the second operation each time the first operation is performed. Alternatively, the control unit 80 may be configured to repeatedly perform the first operation by rotating shaft 20 one revolution along the circumference of bottom bearing 50, and to switch the signal (or data value) of the displacement sensor 70, which is the object of monitoring, to perform the second operation each time the first operation is performed.

[0218] The control unit 80 can consist of a single processor and a memory, or multiple processors and memories. These multiple processors and memories can be housed in a single device (housing) or in separate devices (housings). For example, the processor performing the second action can be the same as or a different processor performing the first action. Furthermore, the storage unit 85 can consist of a single storage device or multiple storage devices.

[0219] Furthermore, while embodiments and variations have been described, it should be understood that various changes in manner and detail can be made without departing from the spirit and scope of the claims. Additionally, elements of the above embodiments, variations, and other embodiments can be appropriately combined or substituted.

[0220] (Postscript)

[0221] This disclosure can also be made in the following manner.

[0222] The first approach relates to a bearing system comprising: a shaft 20; a support portion 11 that supports the shaft 20 in a non-contact manner using electromagnetic force; a bottom bearing 50 that supports the shaft 20 by contacting the shaft 20 when the support portion 11 is not supporting the shaft 20 in a non-contact manner; a plurality of displacement sensors 70 disposed around the shaft 20, each outputting a signal whose amplitude varies according to the distance between the displacement sensor 70 and the shaft 20; and a control unit 80 that performs a first action and a second action. In the first action, the control portion 11 is controlled such that the shaft 20 moves circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50. In the second action, if the amplitude change of the signal output from at least one of the plurality of displacement sensors 70 during the first action is not the amplitude change that occurs when the shaft 20 moves circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, a first message indicating an anomaly is output.

[0223] In the first embodiment, if abnormal contact occurs in the bearing system 10, during the period of abnormal contact during the first operation, the shaft 20 cannot move circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, during the period of abnormal contact, the amplitude change of the signal output from the displacement sensor 70 becomes a different amplitude change than the amplitude change when the shaft 20 moves circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, by outputting first information when the amplitude change of the signal output from the displacement sensor 70 is not the aforementioned amplitude change, it is possible to notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0224] In the second type of bearing system, in the first type of bearing system, the amplitude change of the signal is the change in the amplitude of the signal relative to the position of the shaft 20 in the circumferential direction of the bottom bearing 50.

[0225] In the second approach, by monitoring the change in amplitude of the signal (output from displacement sensor 70) relative to the change in the circumferential position of shaft 20 in the bottom bearing 50, the first information can be appropriately output even when the moving speed of shaft 20 is not constant (when the change in amplitude of the signal relative to the passage of time is not constant). Thus, it is possible to appropriately notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0226] In the bearing system of the third type, in the bearing system of the second type, during the second operation, if the waveform of the amplitude change of the signal output from at least one of the plurality of displacement sensors 70 when the first operation is performed does not have the linear symmetry of the shaft 20 moving circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, the control unit 80 outputs the first information.

[0227] In the third approach, when no abnormal contact occurs in the bearing system 10, during the first operation, the increase and decrease in distance between the shaft 20 and the displacement sensor 70 are symmetrical. As a result, the waveform representing the amplitude change of the signal output from the displacement sensor 70 includes a waveform portion that has a shape representing a linear symmetry corresponding to the increase or decrease in the symmetry of the distance between the shaft 20 and the displacement sensor 70. On the other hand, when abnormal contact occurs in the bearing system 10, the symmetry of the increase and decrease in distance between the shaft 20 and the displacement sensor 70 is disrupted. As a result, when the waveform representing the amplitude change of the signal output from the displacement sensor 70 no longer has the aforementioned linear symmetry, first information is output. Thus, it is possible to notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0228] In the fourth type of bearing system, the control unit 80 monitors the signals output by two or more of the plurality of displacement sensors 70 during the second operation.

[0229] In the fourth method, by monitoring the signals output from two or more displacement sensors 70, the first information can be output with high precision compared to monitoring the signal output from only one displacement sensor 70. Therefore, it is possible to notify with high precision that an anomaly (specifically, abnormal contact) has occurred in the bearing system 10.

[0230] In the bearing system of the fifth type, in the bearing system of the second type, during the second operation, if the trajectory of the shaft 20 is not the trajectory of the shaft 20 moving circumferentially along the bottom bearing 50 while in contact with the inner circumferential surface of the bottom bearing 50, the control unit 80 outputs the first information, wherein the trajectory of the shaft 20 is derived based on the amplitude change of the signals output by two or more of the plurality of displacement sensors 70 when the first operation is performed.

[0231] In the fifth method, if abnormal contact occurs in the bearing system 10, during the period of abnormal contact during the first operation, the shaft 20 cannot move circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, during the period of abnormal contact, the trajectory of the shaft 20 becomes a different shape from the trajectory of the shaft 20 moving circumferentially along the bottom bearing 50 while simultaneously contacting the inner circumferential surface of the bottom bearing 50. Therefore, if the trajectory of the shaft 20 is not the aforementioned trajectory, by outputting the first information, it is possible to notify that an abnormality (specifically, abnormal contact) has occurred in the bearing system 10.

[0232] The sixth type of bearing system includes a magnetic bearing 30 in any of the first to fifth types of bearing systems. The magnetic bearing 30 has a plurality of electromagnets 35 disposed around the shaft 20, and the shaft 20 is supported in a non-contact manner by means of the combined electromagnetic force of the plurality of electromagnets 35. The support part 11 is the magnetic bearing 30.

[0233] The bearing system of the seventh type includes a bearingless motor 90 in any of the bearing systems of the first to fifth types. The bearingless motor 90 has a support winding 95 that generates an electromagnetic force for supporting the shaft 20 in a non-contact manner by means of energization and a drive winding 96 that generates an electromagnetic force for driving the shaft 20 to rotate by means of energization. The support part 11 is the bearingless motor 90.

[0234] The eighth type is a turbine compressor with a bearing system that has any of the first to seventh types.

[0235] The ninth method is a refrigeration system with a turbo compressor, which is the same as the eighth method.

[0236] Industrial availability

[0237] As explained above, this disclosure is useful as a method for detecting anomalies in bearing systems, turbo compressors, refrigeration systems, and bearing systems.

[0238] Label Explanation

[0239] 1 Turbine compressor

[0240] 10 bearing system

[0241] 11 Support section

[0242] 12 drive units

[0243] 20-axis

[0244] 30 radial magnetic bearing (magnetic bearing)

[0245] 35 electromagnet

[0246] 40 thrust magnetic bearing

[0247] 50 bottom contact bearing

[0248] 60 motor

[0249] 70 Radial Displacement Sensor (Displacement Sensor)

[0250] 75 Thrust Displacement Sensor

[0251] 80 Control Department

[0252] 85 Storage Unit

[0253] 90 bearingless motor

[0254] 95 support winding

[0255] 96 drive winding

Claims

1. A bearing system comprising: Shaft (20); The support part (11) supports the shaft (20) in a non-contact manner using electromagnetic force; A bottom-contact bearing (50) supports the shaft (20) by contacting the shaft (20) when the support portion (11) does not support the shaft (20) in a non-contact manner. A displacement sensor (70), disposed around the shaft (20), outputs a signal whose amplitude varies according to the distance between the displacement sensor (70) and the shaft (20); and Control unit (80) The control unit (80) performs a first action and a second action. In the first action, it controls the support unit (11) so that the shaft (20) moves circumferentially along the bottom bearing (50) while in contact with the inner circumferential surface of the bottom bearing (50). In the second action, it outputs a first message indicating an anomaly when the waveform representing the change in data value does not have linear symmetry. The data value changes according to the amplitude change of the signal output from the displacement sensor (70) when the first action is performed.

2. The bearing system according to claim 1, wherein, The bearing system includes a first displacement sensor (70a) and a second displacement sensor (70b), which are arranged around the shaft (20) and output signals whose amplitude varies according to the distance between them and the shaft (20). The position of the second displacement sensor (70b) in the circumferential direction is different from the position of the first displacement sensor (70a) in the circumferential direction. The displacement sensor (70) is either the first displacement sensor (70a) or the second displacement sensor (70b). The control unit (80) monitors a first data value and a second data value during the second operation. The first data value changes according to the amplitude change of the signal output from the first displacement sensor (70a) when the first operation is performed, and the second data value changes according to the amplitude change of the signal output from the second displacement sensor (70b) when the first operation is performed.

3. The bearing system according to claim 2, wherein, In the second action, if the waveform representing the change of the first data value or the waveform representing the change of the second data value does not have the line symmetry, the control unit (80) outputs the first information.

4. The bearing system according to any one of claims 1 to 3, wherein, The bearing system includes a magnetic bearing (30) having a plurality of electromagnets (35) arranged around the shaft (20), which support the shaft (20) in a non-contact manner by means of the combined electromagnetic force of the plurality of electromagnets (35). The support (11) is the magnetic bearing (30).

5. The bearing system according to any one of claims 1 to 3, wherein, The bearing system includes a bearingless motor (90), which has a support winding (95) that generates an electromagnetic force by energizing to support the shaft (20) in a non-contact manner and a drive winding (96) that generates an electromagnetic force by energizing to drive the shaft (20) to rotate. The support (11) is the bearingless motor (90).

6. A turbo compressor comprising the bearing system according to any one of claims 1 to 5.

7. A refrigeration system comprising the turbo compressor of claim 6.

8. A method for detecting anomalies in a bearing system, the bearing system comprising: a shaft (20); a support (11) that supports the shaft (20) in a non-contact manner using electromagnetic force; a bottom-contact bearing (50) that supports the shaft (20) by contact with the shaft (20) when the support (11) does not support the shaft (20) in a non-contact manner; and a displacement sensor (70) disposed around the shaft (20) and outputting a signal whose amplitude varies according to the distance between the displacement sensor (70) and the shaft (20), wherein, The anomaly detection method has the following features: In the first step, the support part (11) is controlled so that the shaft (20) moves along the circumferential direction of the bottom bearing (50) while in contact with the inner circumferential surface of the bottom bearing (50); as well as In the second step, if the waveform representing the change in data value does not have linear symmetry, a first message indicating an anomaly is output, wherein the data value changes according to the amplitude change of the signal output from the displacement sensor (70) during the first step.

9. The method for detecting anomalies in a bearing system according to claim 8, wherein, The bearing system includes a first displacement sensor (70a) and a second displacement sensor (70b), which are disposed around the shaft (20) and output signals whose amplitude varies according to the distance between them and the shaft (20). The position of the second displacement sensor (70b) in the circumferential direction is different from the position of the first displacement sensor (70a) in the circumferential direction. The displacement sensor (70) is either the first displacement sensor (70a) or the second displacement sensor (70b). In the second step, if the waveform representing the change of the first data value or the waveform representing the change of the second data value does not have the said line symmetry, the first information is output, wherein the first data value changes according to the amplitude change of the signal output from the first displacement sensor (70a) when the first step is performed, and the second data value changes according to the amplitude change of the signal output from the second displacement sensor (70b) when the first step is performed.

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