Turbo compressor and assembly method of the same

Abstract

To inhibit damage of a radial magnetic bearing.SOLUTION: A turbo compressor 1 includes: an impeller 11 which compresses a refrigerant; a drive shaft 10 which rotates the impeller 11; a motor 16 which rotationally drives the drive shaft 10; a first radial magnetic bearing 15 which rotatably supports the drive shaft 10 in a non-contact manner; a first touch down bearing 12 which may rotatably support the drive shaft 10 and is spaced apart from the drive shaft 10 in a state where the drive shaft 10 is supported by the first radial magnetic bearing 15; and a first preliminary support structure 13 which may rotatably support the drive shaft 10 and is spaced apart from the drive shaft 10 in a state where the drive shaft 10 is supported by the first radial magnetic bearing 15. A clearance between the drive shaft 10 and the first preliminary support structure 13 is longer than a clearance between the drive shaft 10 and the first touch down bearing 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a turbocompressor and a method for assembling a turbocompressor. [Background technology]

[0002] A turbo chiller equipped with a compressor that drives an impeller with an electric motor is known (for example, Patent Document 1). Patent Document 1 discloses a turbo compressor that includes an electric motor, a drive shaft that rotates by the driving force of the electric motor, a radial magnetic bearing that rotatably supports the drive shaft in a non-contact state, a backup bearing that functions as a bearing when the radial magnetic bearing is stopped, and a support part that supports the drive shaft when the backup bearing is removed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-180069 Summary of the Invention [Problem to be solved by the invention]

[0004] In the turbo compressor of Patent Document 1, only one backup bearing is provided for each radial magnetic bearing. Therefore, if the backup bearing is damaged due to frequent occurrences of supporting the drive shaft, the radial magnetic bearing and the drive shaft may come into contact, potentially damaging the radial magnetic bearing.

[0005] The present disclosure has been made in view of the above circumstances, and has an object to provide a turbo compressor and a method for assembling a turbo compressor that can suppress damage to the radial magnetic bearing. [Means for solving the problem]

[0006] In order to solve the above problems, the turbo compressor and the method for assembling the turbo compressor according to the present disclosure employ the following measures. A turbo compressor according to one aspect of the present disclosure includes an impeller that compresses a refrigerant, a drive shaft that rotates the impeller, a motor that rotationally drives the drive shaft, a radial magnetic bearing that rotatably supports the drive shaft without contact, an auxiliary bearing that can rotatably support the drive shaft and is spaced apart from the drive shaft when the drive shaft is supported by the radial magnetic bearing, and a backup support part that can rotatably support the drive shaft and is spaced apart from the drive shaft when the drive shaft is supported by the radial magnetic bearing, wherein the distance between the drive shaft and the backup support part is longer than the distance between the drive shaft and the backup bearing.

[0007] A method for assembling a turbo compressor according to one aspect of the present disclosure includes the turbo compressor including an impeller that compresses a refrigerant, a drive shaft that rotates the impeller, a motor that rotationally drives the drive shaft, a radial magnetic bearing that rotatably supports the drive shaft without contact, an auxiliary bearing that can rotatably support the drive shaft and that is spaced from the drive shaft when the drive shaft is supported by the radial magnetic bearing, and a backup support part that can rotatably support the drive shaft and that is spaced from the drive shaft when the drive shaft is supported by the radial magnetic bearing, wherein the distance between the drive shaft and the backup support part is longer than the distance between the drive shaft and the backup bearing, and the method includes installing the radial magnetic bearing in a state where the radial magnetic bearing and the drive shaft are spaced apart when the backup support part supports the drive shaft. [Effects of the Invention]

[0008] According to the present disclosure, damage to the radial magnetic bearing can be suppressed. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a cross-sectional side view of a turbo compressor according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a side cross-sectional view showing a turbo compressor according to a modified example of an embodiment of the present disclosure. [Figure 3] FIG. 10 is a side cross-sectional view showing a turbo compressor according to a modified example of an embodiment of the present disclosure. [Figure 4] FIG. 10 is a side cross-sectional view showing a turbo compressor according to a modified example of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a turbo compressor according to the present disclosure will be described with reference to the drawings. The turbo compressor 1 according to this embodiment is installed in a turbo chiller. The turbo chiller includes the turbo compressor 1 that compresses a refrigerant, a condenser (not shown) that condenses the high-temperature, high-pressure gas refrigerant compressed by the turbo compressor 1, an expansion valve (not shown) that expands the liquid refrigerant from the condenser (not shown), and an evaporator (not shown) that evaporates the liquid refrigerant expanded by the expansion valve (not shown).

[0011] 1, the turbo compressor 1 includes a housing (not shown) that forms an outer shell, a drive shaft 10 provided inside the housing, and an impeller 11 provided at one end (the right end in FIG. 1) of the drive shaft 10. In addition, the drive shaft 10 is provided with, in order from the one end (the right end in FIG. 1), a first touchdown bearing (auxiliary bearing) 12, a first auxiliary support structure (auxiliary support portion) 13, a first displacement sensor 14, a first radial magnetic bearing (radial magnetic bearing) 15, and an electric motor 16.

[0012] The turbo compressor 1 also includes a thrust magnetic bearing 21 provided at the other end (left end in FIG. 1) of the drive shaft 10. The drive shaft 10 is provided with, in order from the other end (left end in FIG. 1), a second touchdown bearing (auxiliary bearing) 22, a second auxiliary support structure (auxiliary support portion) 23, a second displacement sensor 24, and a second radial magnetic bearing (radial magnetic bearing) 25.

[0013] The drive shaft 10 rotates the impeller 11. The drive shaft 10 extends in the axial direction inside the housing. The drive shaft 10 extends in a substantially horizontal direction (lateral direction). The impeller 11 compresses the refrigerant sucked into the turbo compressor 1. The impeller 11 is formed by a plurality of blades.

[0014] The electric motor 16 drives the drive shaft 10 to rotate. The electric motor 16 has a stator 16a and a rotor 16b. The stator 16a is fixed to the inner wall of the housing. The stator 16a is a cylindrical member made of a magnetic material. The rotor 16b is disposed radially inside the stator 16a. The rotor 16b is fixed to the drive shaft 10. The rotor 16b is a cylindrical member made of a magnetic material.

[0015] The thrust magnetic bearing 21 has a disk 21a fixed to the drive shaft 10 and multiple pairs of thrust magnetic bearing coils 21b provided on both sides of the disk 21a. The disk 21a is positioned in the thrust direction by the multiple pairs of thrust magnetic bearing coils 21b while it is levitated. This allows the positions of the drive shaft 10 and the impeller 11 in the thrust direction to be accurately determined.

[0016] The first radial magnetic bearing 15, the first displacement sensor 14, the first auxiliary support structure 13, and the first touchdown bearing 12, and the second radial magnetic bearing 25, the second displacement sensor 24, the second auxiliary support structure 23, and the second touchdown bearing 22 are arranged symmetrically with respect to a vertical plane passing through the axial center of the electric motor 16. Therefore, in the following, we will explain the first radial magnetic bearing 15, the first displacement sensor 14, the first auxiliary support structure 13, and the first touchdown bearing 12, and will omit detailed explanations of the second radial magnetic bearing 25, the second displacement sensor 24, the second auxiliary support structure 23, and the second touchdown bearing 22.

[0017] First radial magnetic bearing 15 supports drive shaft 10 rotatably without contact with the housing. First radial magnetic bearing 15 is a bearing for supporting a load acting in the radial direction (radial load) among the loads acting on drive shaft 10. When first radial magnetic bearing 15 supports drive shaft 10, the inner peripheral surface of first radial magnetic bearing 15 and the outer peripheral surface of drive shaft 10 are spaced apart.

[0018] The first displacement sensor detects the displacement of the first radial magnetic bearing 15. More specifically, the first displacement sensor detects the displacement of the first radial magnetic bearing 15 relative to the drive shaft .

[0019] The first auxiliary support structure 13 is provided between the first radial magnetic bearing 15 and the first touchdown bearing 12. In this embodiment, the first auxiliary support structure 13 is a ball bearing, as shown in Fig. 1. When the first radial magnetic bearing 15 supports the drive shaft 10, the inner circumferential surface of the first auxiliary support structure 13 and the outer circumferential surface of the drive shaft 10 are spaced apart. The first auxiliary support structure 13 is capable of rotatably supporting the drive shaft 10, and is spaced apart from the drive shaft 10 when the drive shaft 10 is supported by the first radial magnetic bearing 15.

[0020] The first touchdown bearing 12 is a mechanical auxiliary bearing. The first touchdown bearing 12 rotatably supports the drive shaft 10 when the drive shaft 10 is not supported by the first radial magnetic bearing 15 or the thrust magnetic bearing 21. The first touchdown bearing 12 is used when the first radial magnetic bearing 15 or the thrust magnetic bearing 21 is unstable. The first touchdown bearing 12 is also used to support the drive shaft 10 so that it does not come into contact with the first radial magnetic bearing 15 or the thrust magnetic bearing 21, the first displacement sensor 14, etc. before control of the turbo compressor 1 is started or ended.

[0021] The distance d1 between the inner peripheral surface of the first auxiliary support structure 13 and the outer peripheral surface of the drive shaft 10 is longer than the distance d2 between the inner peripheral surface of the first touchdown bearing 12 and the outer peripheral surface of the drive shaft 10.

[0022] When the drive shaft 10 is supported by the first radial magnetic bearing 15, the first touchdown bearing 12 does not support the drive shaft 10. Furthermore, when the drive shaft 10 is supported by the first radial magnetic bearing 15, the first auxiliary support structure 13 does not support the drive shaft 10. Furthermore, when the drive shaft 10 is supported by the first touchdown bearing 12, the first auxiliary support structure 13 does not support the drive shaft 10.

[0023] Furthermore, when the first touchdown bearing 12 supports the drive shaft 10, the drive shaft 10 is not in contact with the first radial magnetic bearing 15 or the first displacement sensor 14. Furthermore, when the first auxiliary support structure 13 supports the drive shaft 10, the drive shaft 10 is not in contact with the first radial magnetic bearing 15 or the first displacement sensor 14.

[0024] The first auxiliary support structure 13 may be used when assembling the turbo compressor 1. Specifically, the first radial magnetic bearing 15 may be installed in a state where the first auxiliary support structure 13 supports the drive shaft 10. By assembling in this manner, the first radial magnetic bearing 15 does not come into contact with the drive shaft 10 when installing the first radial magnetic bearing 15. This makes it easier to assemble the first radial magnetic bearing 15. This makes it easier to assemble the turbo compressor.

[0025] The first auxiliary support structure 13 may also be used during maintenance of the turbo compressor 1. Specifically, the first touchdown bearing 12 may be replaced while the first auxiliary support structure 13 is supporting the drive shaft 10. By performing maintenance in this manner, the first touchdown bearing 12 does not come into contact with the drive shaft 10 during maintenance. This makes it easier to perform maintenance on the first touchdown bearing 12. This makes it easier to perform maintenance on the turbo compressor 1.

[0026] According to this embodiment, the following advantageous effects are achieved. In this embodiment, the distance d1 between the drive shaft 10 and the first auxiliary support structure 13 and / or the second auxiliary support structure 23 is longer than the distance d2 between the drive shaft 10 and the first touchdown bearing 12 and / or the second touchdown bearing 22. As a result, in the event that the first radial magnetic bearing 15 and / or the second radial magnetic bearing 25 cannot support the drive shaft 10 in a non-contact manner, the first touchdown bearing 12 and / or the second touchdown bearing 22, which are provided near the drive shaft 10, will first support the drive shaft 10.

[0027] At this time, the first auxiliary support structure 13 and / or the second auxiliary support structure 23 does not support the drive shaft 10. Furthermore, when a situation arises in which not only the first radial magnetic bearing 15 and the second radial magnetic bearing 25 but also the first touchdown bearing 12 and the second touchdown bearing 22 are unable to support the drive shaft 10, the first auxiliary support structure 13 and / or the second auxiliary support structure 23 supports the drive shaft 10. As described above, in this embodiment, even if both the radial magnetic bearing and the touchdown bearing are unable to support the drive shaft 10, the drive shaft 10 can be supported by the first auxiliary support structure 13 and / or the second auxiliary support structure 23, making it difficult for the drive shaft 10 to come into contact with the radial magnetic bearing. This makes it possible to suppress damage to the radial magnetic bearing due to contact between the drive shaft 10 and the radial magnetic bearing.

[0028] The present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure.

[0029] For example, in the above embodiment, the first auxiliary support structure 13 and the second auxiliary support structure 23 are described as ball bearings, but the present disclosure is not limited to this. For example, as shown in Fig. 2, the first auxiliary support structure 13A and the second auxiliary support structure 23A may be plain bearings (carbon bearings). Also, as shown in Fig. 3, the first auxiliary support structure 13B and the second auxiliary support structure 23B may be ring-shaped members.

[0030] Furthermore, in the above embodiment, an example has been described in which the present disclosure is applied to a turbo compressor 1 in which the thrust magnetic bearing 21 is provided at the other end (the left end in FIG. 1) of the drive shaft 10, but the present disclosure is not limited to this. For example, as shown in FIG. 4, the present disclosure may be applied to a turbo compressor 1 in which the thrust magnetic bearing 21 is provided at approximately the center of the drive shaft 10.

[0031] The turbo compressor according to the embodiment described above can be understood, for example, as follows. A turbo compressor according to a first aspect of the present disclosure includes an impeller (11) that compresses a refrigerant, a drive shaft (10) that rotates the impeller (11), a motor (16) that rotationally drives the drive shaft (10), radial magnetic bearings (15, 25) that rotatably support the drive shaft (10) without contact, and a radial magnetic bearing (15, 25) that can rotatably support the drive shaft (10) and that, when the drive shaft (10) is supported by the radial magnetic bearings (15, 25), The magnetic bearing (15, 25) includes an auxiliary bearing (12, 22) spaced apart from the drive shaft (10), and a backup support part (13, 23) that can rotatably support the drive shaft (10) and that is spaced apart from the drive shaft (10) when the drive shaft (10) is supported by the radial magnetic bearing (15, 25), and the distance between the drive shaft (10) and the backup support part (13, 23) is longer than the distance between the drive shaft (10) and the backup bearing (12, 22).

[0032] In the above configuration, the distance between the drive shaft and the auxiliary support part is longer than the distance between the drive shaft and the auxiliary bearing. As a result, if the radial magnetic bearing becomes unable to support the drive shaft due to non-contact, the auxiliary bearing located near the drive shaft will first support the drive shaft. In this case, the auxiliary support part does not support the drive shaft. Furthermore, if neither the radial magnetic bearing nor the auxiliary bearing can support the drive shaft, the auxiliary support part supports the drive shaft. Thus, with the above configuration, even if both the radial magnetic bearing and the auxiliary bearing are unable to support the drive shaft, the auxiliary support part can support the drive shaft, making it less likely for the drive shaft and the radial magnetic bearing to come into contact. This reduces damage to the radial magnetic bearing due to contact between the drive shaft and the radial magnetic bearing.

[0033] In a method for assembling a turbo compressor according to a first aspect of the present disclosure, the turbo compressor (1) includes an impeller (11) that compresses a refrigerant, a drive shaft (10) that rotates the impeller (11), a motor (16) that rotationally drives the drive shaft (10), radial magnetic bearings (15, 25) that rotatably support the drive shaft (10) without contact, auxiliary bearings (12, 22) that are capable of rotatably supporting the drive shaft (10) and are spaced apart from the drive shaft (10) in a state in which the drive shaft (10) is supported by the radial magnetic bearings (15, 25), and auxiliary bearings (12, 22) that are capable of rotatably supporting the drive shaft (10) and are spaced apart from the drive shaft (10) in a state in which the drive shaft (10) is supported by the radial magnetic bearings (15, 25). and a step of installing the radial magnetic bearings (15, 25) in a state in which the radial magnetic bearings (15, 25) are spaced apart from the drive shaft (10) when the drive shaft (10) is supported by the auxiliary bearings (12, 22), the distance between the drive shaft (10) and the auxiliary support parts (13, 23) being longer than the distance between the drive shaft (10) and the auxiliary bearings (12, 22), and the radial magnetic bearings (15, 25) are spaced apart from the drive shaft (10) when the auxiliary support parts (13, 23) support the drive shaft (10).

[0034] In the above configuration, when the auxiliary support part supports the drive shaft, the radial magnetic bearing and the drive shaft are spaced apart. Furthermore, when the auxiliary support part supports the drive shaft, the radial magnetic bearing is installed. This prevents the radial magnetic bearing from coming into contact with the drive shaft when the radial magnetic bearing is installed. This makes it easier to assemble the radial magnetic bearing. This also simplifies the assembly work of the turbo compressor. [Explanation of symbols]

[0035] 1: Turbo compressor 10: Drive shaft 11: Impeller 12: First touchdown bearing (auxiliary bearing) 13: First auxiliary support structure (auxiliary support structure) 14: First displacement sensor 15: First radial magnetic bearing (radial magnetic bearing) 16: Electric motor 16a: Stator 16b: Rotor 21: Thrust magnetic bearing 21a: disk 21b: Thrust magnetic bearing coil 22: Second touchdown bearing (auxiliary bearing) 23: Second auxiliary support structure (auxiliary support structure) 24: Second displacement sensor 25: Second radial magnetic bearing (radial magnetic bearing) d1: distance d2: distance

Claims

1. an impeller that compresses the refrigerant; a drive shaft that rotates the impeller; a motor that rotates the drive shaft; a radial magnetic bearing that rotatably supports the drive shaft in a non-contact manner; an auxiliary bearing capable of rotatably supporting the drive shaft and spaced apart from the drive shaft when the drive shaft is supported by the radial magnetic bearing; a backup support portion capable of rotatably supporting the drive shaft and spaced apart from the drive shaft when the drive shaft is supported by the radial magnetic bearing; a distance between the drive shaft and the auxiliary support portion being longer than a distance between the drive shaft and the auxiliary bearing;

2. A method for assembling a turbo compressor, comprising the steps of: The turbo compressor is an impeller that compresses the refrigerant; a drive shaft that rotates the impeller; a motor that rotates the drive shaft; a radial magnetic bearing that rotatably supports the drive shaft in a non-contact manner; an auxiliary bearing capable of rotatably supporting the drive shaft and spaced apart from the drive shaft when the drive shaft is supported by the radial magnetic bearing; a backup support portion capable of rotatably supporting the drive shaft and spaced apart from the drive shaft when the drive shaft is supported by the radial magnetic bearing; a distance between the drive shaft and the auxiliary support portion is longer than a distance between the drive shaft and the auxiliary bearing; When the auxiliary support part supports the drive shaft, the radial magnetic bearing and the drive shaft are spaced apart from each other, a step of installing the radial magnetic bearing in a state in which the auxiliary support portion supports the drive shaft.

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