CN219067999U - Rotor system for centrifugal compressor and permanent magnet synchronous motor - Google Patents

Abstract

The utility model discloses a rotor system for a centrifugal compressor, which comprises a rotor and a radial bearing, wherein the radial bearing is arranged on the rotor and is an air bearing. By adopting the air bearing, the reliability of the centrifugal compressor can be improved, and the volume and weight of the centrifugal compressor can be reduced.

Description

Rotor system for centrifugal compressor and permanent magnet synchronous motor

Technical Field

The utility model relates to the technical field of air compression, in particular to a rotor system for a centrifugal compressor and a permanent magnet synchronous motor.

Background

Currently, scroll compressors can be applied to liquid cooling systems, and most of scroll compressors adopt oil circulation, which easily reduces the reliability of the compressors and the liquid cooling systems. In addition, the bearings in scroll compressors are typically contact ball bearings, which are subject to wear, and therefore their life is often a bottleneck for the life of the liquid cooling system. Meanwhile, the volume and the mass of the scroll compressor are large, and when the scroll compressor is applied to equipment such as an energy storage system and the like which need thermal management, the energy density of the energy storage system is not beneficial to improvement, and particularly, as the power density of the energy storage system is increased, the refrigerating capacity requirement is obviously increased, and the disadvantage of the scroll compressor in the aspect of the aspect is more remarkable.

Disclosure of Invention

In view of some or all of the problems of the prior art, a first aspect of the present utility model provides a rotor system for a centrifugal compressor employing an air bearing, the rotor system comprising:

a rotor; and

a radial bearing provided on the rotor to support the rotor in a radial direction of the rotor, wherein the radial bearing is an air bearing.

Further, the rotor system comprises two radial bearings, and a space is arranged between the two radial bearings.

Further, the two radial bearings are symmetrically distributed on the rotor.

Further, the radial bearing is a foil dynamic pressure air bearing.

Further, the rotor system further includes:

a thrust plate provided at an end of the rotor; and

and the thrust bearing is arranged on one side or two sides of the thrust disc.

Further, the thrust bearing is a foil dynamic pressure air bearing.

Further, the rotor system comprises a thrust disc, wherein two sides of the thrust disc are respectively provided with a thrust bearing, and the two thrust bearings are arranged in opposite directions.

Further, the rotor system comprises two thrust disks symmetrically distributed on the rotor.

Further, one side of the two thrust discs opposite to each other is respectively provided with a thrust bearing, and the two thrust bearings are arranged in a back-to-back mode; and/or

One side of the two thrust disks, which is away from each other, is respectively provided with a thrust bearing, and the two thrust bearings are arranged in opposite directions.

Based on the rotor system as described above, a first aspect of the present utility model provides a permanent magnet synchronous motor applicable to a centrifugal compressor, comprising:

a housing;

a stator fixed to an inside of the housing; and

a rotor system as hereinbefore described wherein the central axis of the rotor coincides with the central axis of the stator.

The rotor system and the motor for the centrifugal compressor adopt the air bearing, so that lubricating oil is not required, and an oil return pipeline can be omitted. Meanwhile, the rotating shaft is not contacted with the bearing when the air bearing works, but the motor rotor is suspended by the air film, so that the service life of the bearing can be prolonged by at least 1 time. In addition, under the same cold energy, the size and weight of the centrifugal compressor based on the high-speed permanent magnet synchronous motor can be about 50% smaller than those of the scroll compressor, and the mass can be reduced by about 90%.

Drawings

To further clarify the above and other advantages and features of embodiments of the present utility model, a more particular description of embodiments of the utility model will be rendered by reference to the appended drawings. It is appreciated that these drawings depict only typical embodiments of the utility model and are therefore not to be considered limiting of its scope. In the drawings, for clarity, the same or corresponding parts will be designated by the same or similar reference numerals.

FIG. 1 shows a schematic configuration of an air bearing centrifugal compressor in accordance with one embodiment of the utility model;

FIGS. 2a-2d are schematic views each showing a configuration of an air bearing centrifugal compressor according to other embodiments of the present utility model;

FIGS. 3a-3d are schematic views each showing a configuration of a different rotor system in an air bearing centrifugal compressor according to an embodiment of the utility model;

FIG. 4 shows a schematic diagram of a low-coldness air-bearing centrifugal compressor for energy storage thermal management in accordance with an embodiment of the present utility model; and

fig. 5 shows a schematic cross-sectional view of a low-refrigeration air-bearing centrifugal compressor for energy storage thermal management according to an embodiment of the utility model.

Detailed Description

In the following description, the present utility model is described with reference to various embodiments. One skilled in the relevant art will recognize, however, that the embodiments may be practiced without one or more of the specific details, or with other alternative and/or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the utility model. Similarly, for purposes of explanation, specific numbers, materials and configurations are set forth in order to provide a thorough understanding of the embodiments of the utility model. However, the utility model is not limited to these specific details. Furthermore, it should be understood that the embodiments shown in the drawings are illustrative representations and are not necessarily drawn to scale.

Reference throughout this specification to "one embodiment" or "the embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present utility model. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

It should be noted that the embodiments of the present utility model describe the process steps in a specific order, however, this is merely to illustrate the specific embodiment and not to limit the order of the steps. In contrast, in various embodiments of the present utility model, the order of the steps may be adjusted according to process adjustments.

In embodiments of the present utility model, the term "main gas path" refers to a gas path through which gas enters a compressor along a gas inlet, is compressed, and exits through a gas outlet. The term "high pressure side" refers to the side of the compressor where the air pressure is higher, i.e. the side where the last stage impeller is located, and the term "low pressure side" refers to the side of the compressor interior opposite to the high pressure side. Under normal conditions, the gas flows from the high pressure side to the low pressure side through the air bearing and then returns to the main gas path.

In order to improve the reliability of the compressor and reduce the size and weight of the compressor, the utility model provides the air-floating centrifugal compressor. The embodiments of the present utility model will be further described with reference to the drawings.

Fig. 1 and 2a-2d show schematic configuration diagrams of an air-floating centrifugal compressor according to various embodiments of the utility model. As shown, in the embodiment of the present utility model, the air-floating centrifugal compressor includes a motor and an impeller 200. The rotor system of the motor comprises a radial air bearing 111, when the motor shaft rotates, the radial air bearing sucks gas to form a gas film to support the rotor to rotate at a high speed, and meanwhile, the thrust bearing (if any) also forms a gas film, so that the thrust shaft is not contacted with the bearing, the bearing is almost free from abrasion, and mechanical loss and noise can be greatly reduced or even eliminated. As shown, the impeller 200 is provided at an end of the rotor 101 for compressing a low temperature and low pressure refrigerant gas from an evaporator to form a high temperature and high pressure refrigerant gas to be discharged into a condenser. Herein, the terms "radial" and "axial" refer to the radial and axial directions of the rotor or its rotational axis.

Figures 3a-3d show schematic views of different rotor systems in an air bearing centrifugal compressor according to an embodiment of the utility model, respectively. As shown, in the embodiment of the present utility model, the rotor system 101 includes two radial bearings, which have a certain distance therebetween and may be symmetrically distributed on the rotor. In one embodiment of the utility model, the radial bearing adopts a foil dynamic pressure air bearing, and when gas is introduced into the bearing position, a gas film can be formed, so that the air bearing effect is achieved.

In order to withstand the axial thrust forces generated during operation of the compressor, in one embodiment of the utility model, a thrust disc 112 and a thrust bearing 113 are also provided in the rotor system. Thrust disc 112 and thrust bearing 113 are optional. As shown in fig. 3a-3d, the thrust disc 112 may be disposed at either end of the rotor, or one thrust disc 112 may be disposed at each end of the rotor. When only one thrust disc is provided, one thrust bearing 113 may be provided on each side of the thrust disc 112, as shown in the figure, the acting surfaces of the two thrust bearings 113 face the thrust disc 112, so that axial thrust forces in different directions can be respectively borne, specifically, the axial thrust directions borne by the two thrust bearings 113 are opposite. When two thrust disks are provided, one thrust bearing 113 may be respectively disposed on two opposite sides of the two thrust disks 112, or on two sides far away from each other, as shown in the drawing, the acting surfaces of the two thrust bearings 113 face the thrust disks 112, so that axial thrust in different directions can be respectively borne, specifically, the axial thrust directions borne by the two thrust bearings 113 are opposite. In one embodiment of the utility model, the thrust bearing adopts a foil type dynamic pressure air bearing, and when gas is introduced into the bearing position, a gas film can be formed, so that the air bearing effect is achieved.

As shown in fig. 1 and fig. 2a-2d, in various embodiments of the present utility model, single-stage, double-stage or multi-stage impellers may be provided according to practical requirements. Specifically, when only a single-stage impeller is provided, as shown in fig. 1 and 2a, the impeller 200 may be provided at either end of the rotor, and the side where the impeller is provided may be referred to as the high-pressure side, while the side where the impeller is not provided may be referred to as the low-pressure side. When two stages of impellers are provided, as shown in fig. 2b and 2c, the two impellers may be respectively provided at both ends of the rotor, or may be all provided at any one end of the rotor, and when the two impellers are respectively provided at both ends of the rotor, one side provided with the impeller of the previous stage may be denoted as a low pressure side, and one side provided with the impeller of the subsequent stage may be denoted as a high pressure side, and when the two impellers are all provided at one end of the rotor, one side provided with the impeller may be denoted as a high pressure side, and one side not provided with the impeller may be denoted as a low pressure side. Similarly, as shown in fig. 2d, when the multi-stage impellers are provided, the plurality of impellers may be equally or unequally provided at both ends of the rotor, or may be provided at either end of the rotor, and when the multi-stage impellers are provided at both ends of the rotor, one side provided with the impeller of the previous stage may be referred to as a low pressure side, and one side provided with the impeller of the subsequent stage may be referred to as a high pressure side, and when the multi-stage impellers are provided at one end of the rotor, one side provided with the impeller may be referred to as a high pressure side, and one side not provided with the impeller may be referred to as a low pressure side. Based on this, as shown in fig. 1 and 2a-2d, when the rotor rotates, a part of the high pressure gas compressed by the impeller in the main gas path enters the radial bearing on the high pressure side under the pressure, then enters the radial bearing on the low pressure side through the air gap between the motor stator and the rotor, and returns to the main gas path. When the thrust disc and the thrust bearing are arranged, the high-pressure gas also passes through the thrust bearing to form a gas film to bear axial thrust. In order to effectively reduce the axial thrust force applied to the thrust bearing, in one embodiment of the present utility model, the impeller at the low pressure side and the impeller at the high pressure side are disposed in a back-to-back manner, so that the axial thrust directions of the impellers at the high pressure side and the low pressure side are opposite to each other to cancel each other. In one embodiment of the utility model, the impeller is a shrouded impeller. In one embodiment of the utility model, the impeller is secured to the rotor by a lock nut.

The specific structure and working principle of the air-floating centrifugal compressor according to the embodiment of the utility model will be described in detail below by taking the configuration shown in fig. 2b as an example. It should be understood that the structure and the working principle of the air-floating centrifugal compressor adopting other configurations are basically the same as those of the embodiment, and only the number and positions of the impellers and/or the number and positions of the thrust disks are different, and are not described herein. The air-floating centrifugal compressor in the embodiment is suitable for energy storage heat management, is a small-cooling-capacity air-floating centrifugal compressor, and can be used for an energy storage liquid cooling system.

Fig. 4 and 5 show a schematic structural view and a schematic sectional view of a small-cooling-capacity air-floating centrifugal compressor for energy storage thermal management according to an embodiment of the utility model. As shown, a small cooling capacity air-float centrifugal compressor for energy storage heat management includes a motor 100, an impeller, an air inlet 301, an air outlet 302, and a connection pipe 303.

The motor 100 includes a rotor 101, a stator 102, and a housing 103. The stator 102 is fixed inside the housing 103, and the central axis of the rotor 101 coincides with the central axis of the stator 102. Two radial air bearing 111 are arranged on the rotor 101, meanwhile, a thrust disc 112 is arranged on one side close to the air inlet 301, two air bearing 113 are respectively arranged on two sides of the thrust disc, and the two air bearing are oppositely arranged to respectively bear axial thrust pointing to the low pressure side or the high pressure side.

As shown in the figure, a first chamber and a second chamber are respectively disposed at two ends of the interior of the housing 103. The air inlet of the first chamber is communicated with the air inlet 301 of the compressor, which can be understood that the air inlet 301 is the air inlet of the first chamber, the first chamber is provided with a first impeller 201, and the first impeller 201 is fixed at the first end of the rotor 101. A connection pipe 303 is disposed between the first chamber and the second chamber, and the gas compressed by the first impeller 201 flows out from the gas outlet of the first chamber into the connection pipe 303, and then enters the second chamber through the gas inlet of the second chamber. The second impeller 202 is disposed in the second chamber, the second impeller 202 is fixed at the second end of the rotor 101, most of the gas compressed by the second impeller 202 flows out from the gas outlet of the second chamber, and the gas outlet of the second chamber is communicated with the gas outlet 302 of the compressor, which can also be understood as the gas outlet 302 is the gas outlet of the second chamber. As shown in the drawing, in the embodiment of the present utility model, the air outlets of the first chamber and the second chamber are further provided with a first end cover 135 and a second end cover 136, a gap exists between the first end cover 135 and the second end cover 136 and the rotor 101, meanwhile, a certain gap exists between the first end cover 135 and the first impeller 201, the air flowing through the air bearing can return to the main air path through the gap, a certain gap also exists between the second end cover 136 and the second impeller 202, and a part of the air compressed by the second impeller 202 can enter the air bearing through the gap under the action of pressure. In one embodiment of the present utility model, the first impeller 201 and the second impeller 202 are closed impellers, and compared with open impellers, the closed impellers can effectively eliminate the secondary flow from the blade pressure surface to the suction surface caused by the blade tip clearance, and further can effectively improve the aerodynamic efficiency of the compressor. In one embodiment of the present utility model, as described above, the first impeller 201 and the second impeller 202 are designed back-to-back, so that the axial thrust directions of the first impeller and the second impeller are opposite, and offset each other, thereby effectively reducing the axial thrust received by the thrust bearing. In one embodiment of the present utility model, the first impeller 201 and the second impeller 202 are fixed to the rotor 101 by a first lock nut 211 and a second lock nut 221, respectively.

As shown in the figure, the outer sides of the two ends of the motor are further provided with a first pressing shell 131 and a second pressing shell 132 respectively, a first sealing ring 133 is arranged between the first pressing shell 131 and the first impeller 201, and a second sealing ring 134 is arranged between the second pressing shell 132 and the second impeller 202, and the first sealing ring and the second sealing ring can obviously reduce the backflow effect from the outlet to the inlet of the first impeller and the second impeller, so that the efficiency of the compressor can be further improved.

In order to reduce the compression power consumption of the second impeller 202, in an embodiment of the present utility model, an inter-stage air-filling hole 331 is further provided on the connection pipe 303 to access the exhaust air from the economizer, so as to cool the gas compressed by the first impeller, thereby achieving the purposes of reducing the compression power consumption of the high-pressure impeller and improving the efficiency of the system.

In one embodiment of the present utility model, the motor 100 employs a high-speed permanent magnet synchronous motor, the bearings of which are non-contact bearings during operation, and thus can withstand higher rotational speeds than conventional ball bearings, according to the compressor euler formula Δh=u ₂ Cu ₂ -U ₁ Cu ₁ It is known that the larger the rotation speed is, the smaller the radial dimension is, and therefore, the power density of the compressor can be improved by adopting the permanent magnet synchronous motor.

The working principle of the air-float centrifugal compressor is as follows: the gas compressed by the second impeller enters the second radial bearing at the high pressure side through the gap between the second impeller and the second end cover and the gap between the second end cover and the rotor, then enters the first radial bearing at the low pressure side through the gap between the stator and the rotor, then sequentially passes through the two thrust bearings through the gap between the thrust disc and the motor shell and the gap between the thrust disc and the first end cover, finally sequentially passes through the gap between the first end cover and the rotor and the gap between the first impeller and the gambling end cover, enters the first chamber, namely the exhaust port of the first impeller, and returns to the main gas path to realize internal circulation. Compared with a static pressure air bearing, the air bearing centrifugal compressor can omit an external air supplementing channel, simplify the system structure and improve the reliability.

While various embodiments of the present utility model have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to those skilled in the relevant art that various combinations, modifications, and variations can be made therein without departing from the spirit and scope of the utility model. Thus, the breadth and scope of the present utility model as disclosed herein should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims (10)

1. A rotor system for a centrifugal compressor, comprising:

a rotor; and

a radial bearing provided on the rotor to support the rotor in a radial direction of the rotor, wherein the radial bearing is an air bearing.

2. The rotor system of claim 1, comprising two radial bearings with a space therebetween.

3. The rotor system of claim 2, wherein the two radial bearings are symmetrically distributed on the rotor.

4. The rotor system of claim 1, wherein the radial bearing is a foil dynamic pressure air bearing.

5. The rotor system as recited in claim 1, further comprising:

a thrust plate provided at an end of the rotor; and

and the thrust bearing is arranged on one side or two sides of the thrust disc.

6. The rotor system of claim 5, wherein the thrust bearing is a foil dynamic pressure air bearing.

7. The rotor system of claim 5, comprising a thrust disc, wherein one thrust bearing is disposed on each side of the thrust disc, and wherein the two thrust bearings are disposed opposite each other.

8. The rotor system of claim 5, comprising two thrust plates symmetrically distributed on the rotor.

9. The rotor system of claim 8, wherein the two thrust plates are each provided with a thrust bearing on opposite sides thereof, and wherein the two thrust bearings are disposed in a back-to-back manner; and/or

One side of the two thrust disks, which is away from each other, is respectively provided with a thrust bearing, and the two thrust bearings are arranged in opposite directions.

10. A permanent magnet synchronous motor, comprising:

a housing;

a stator fixed to an inside of the housing; and

a rotor system as claimed in any one of claims 1 to 9, wherein the central axis of the rotor coincides with the central axis of the stator.

Images