Symmetrical permanent magnet motor rotor of centrifugal compressor
By symmetrically arranging the air-floating bearing and airway structure, combining balance screws and limit pins, the problems of insufficient load-bearing capacity and low dynamic balance accuracy caused by asymmetry of the rotor structure in the prior art are solved, and higher stability and dynamics are achieved performance.
Patent Information
- Application Number
- CN202420938752.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-04-30
AI Technical Summary
The rotor structure of the existing centrifugal compressors is asymmetric, resulting in insufficient load-bearing capacity, low dynamic balance accuracy, uneven thermal expansion and cooling, making it difficult to ensure bearing assembly clearance, and the dynamic balance process at high speeds is difficult to perform high precision.
Design a symmetrical permanent magnet motor rotor, symmetrically arrange the first air-floating bearing, the second air-floating bearing and its airway structure, and use balance screws and limit pins to ensure dynamic balance, and use a bidirectional airway structure to achieve suspension and support. , adjust the gap for improved stability and accuracy.
The uniform mass distribution of the rotor structure is achieved, dynamic performance and stability are improved, dynamic balance accuracy and operating stability of the rotor, and assembly consistency of symmetrical layout and performance at high speeds are enhanced.
Smart Images
Figure CN222234513U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of rotors in centrifugal compressors, and particularly relates to a symmetrical permanent magnet motor rotor for a centrifugal compressor. Background Art
[0002] The rotor structure of the gas hydrostatic bearing permanent magnet motor used in the centrifugal compressor must be designed to meet the technical characteristics of the gas hydrostatic bearing. Although the gas hydrostatic bearing has the advantages of high speed, high rotation accuracy, low friction power consumption, etc., its bearing capacity and stiffness are limited by the maximum possible overall size and the minimum air supply pressure required for the bearing to work due to the very thin thickness of the bearing air film, which puts more stringent requirements on the structural layout of the rotor.
[0003] According to the rotor structure described in the Chinese invention patent publication number CN112628281A, a thrust bearing and a radial bearing are arranged at one end of the entire rotor structure, and a radial bearing is arranged alone at the other end, and the entire rotor structure is complex; while the rotor structure described in the Chinese invention patent publication number CN113738661A has a thrust bearing with two thrust surfaces and a radial bearing arranged at one end, and a radial bearing arranged alone at the other end. In the rotor structure layout mentioned in the two patents, the two bearing support positions are asymmetric in shape structure and size relative to the rotor center of gravity, which leads to a large deviation in the composite force caused by radial and axial forces on the two support ends of the rotor; in addition, the asymmetric structure layout is easily affected by the operating temperature, resulting in uneven thermal expansion and contraction of the rotor, and the assembly clearance of the bearing is difficult to guarantee; in addition, the high-speed operation of the rotor puts higher requirements on the dynamic balance (G0.4) of the rotor, and the asymmetric structure layout of the rotor usually makes it difficult to perform the dynamic balancing process with higher precision.
[0004] Regarding the above-mentioned prior art, the technical personnel in this field have studied to make the overall mass distribution of the rotor more uniform through the symmetrical arrangement of the rotor, which is beneficial to improving the dynamic balance performance of the rotor and enhancing the stability of the rotor at high-speed operation. Utility Model Content
[0005] The utility model aims to provide a symmetrical permanent magnet motor rotor for a centrifugal compressor with symmetrical overall rotor layout, high stability and more reasonable structure in view of the defects and shortcomings of the prior art.
[0006] In order to achieve the above-mentioned purpose, the utility model provides a symmetrical permanent magnet motor rotor of a centrifugal compressor, including a magnetic steel, wherein a first shaft section and a second shaft section are respectively arranged on both sides of the magnetic steel in the axial direction, and the magnetic steel is radially covered with a sleeve, the first shaft section includes a third shaft section, a fourth shaft section, and a fifth shaft section with different outer diameters, the fifth shaft section is radially connected to the sleeve, the outer periphery of the fourth shaft section is sleeved with a first air-floating bearing, the outer periphery of the third shaft section is sleeved with a first thrust plate, a first air channel for suspending the first air-floating bearing is arranged between the first thrust plate, the first air-floating bearing, and the fourth shaft section, the second shaft section includes a sixth shaft section, a seventh shaft section, and an eighth shaft section with different outer diameters, the sixth shaft section is radially connected to the sleeve, the outer periphery of the seventh shaft section is sleeved with a second air-floating bearing, the outer periphery of the eighth shaft section is sleeved with a second thrust plate, and a second air channel for suspending the second air-floating bearing is arranged between the second thrust plate, the second air-floating bearing, and the seventh shaft section. The centrifugal compressor supplies air to the air bearing through an external air source. The high-pressure gas suspends the second air bearing and the first air bearing evenly on the seventh shaft segment and the fourth shaft segment through the second air channel and the first air channel, and is placed on the inner side of the second thrust plate and the first thrust plate respectively for axial floating limit. The seventh shaft segment, the second thrust plate, the fourth shaft segment, and the first thrust plate are arranged in sections on both sides of the magnetic steel axis to form a uniform symmetrical structure to further improve the dynamic performance of the permanent magnet motor rotor.
[0007] The fourth shaft segment and the fifth shaft segment are connected by a first inclined plane, and a first balancing screw is arranged on the first inclined plane. The sixth shaft segment and the seventh shaft segment are connected by a second inclined plane, and a second balancing screw is arranged on the second inclined plane. The first balancing screw and the second balancing screw can achieve the dynamic balance requirement of the rotor by adjusting the screw counterweight.
[0008] The spacing between the first balancing screw and the center line of the magnetic steel is equal to the spacing between the second balancing screw and the center line of the magnetic steel. The spacing between the center line of the first air bearing and the center line of the magnetic steel is equal to the spacing between the center line of the second air bearing and the center line of the magnetic steel. The spacing between the first thrust plate and the center line of the magnetic steel is equal to the spacing between the second thrust plate and the center line of the magnetic steel. The symmetry of the triple spacing is conducive to improving the uniformity of the rotor weight on both sides of the center line of the magnetic steel.
[0009] The first air channel includes a first vertical air channel and a first transverse air channel that are interconnected. The first vertical air channel is arranged between the first thrust plate and the first air bearing, and the first transverse air channel is arranged between the fourth shaft section and the first air bearing. The second air channel includes a second vertical air channel and a second transverse air channel that are interconnected. The second vertical air channel is arranged between the second thrust plate and the second air bearing, and the second transverse air channel is arranged between the seventh shaft section and the second air bearing. The first vertical air channel and the first transverse air channel form a transverse and vertical bidirectional suspension structure. Similarly, the second vertical air channel and the second transverse air channel also form a transverse and vertical bidirectional suspension structure. The two form a symmetrical suspension structure on both sides of the magnetic steel axis. The air film in the first transverse air channel and the second transverse air channel forms a radial support force for supporting the radial load of the rotor. The first vertical air channel and the second vertical air channel form an axial support force for supporting the axial thrust load of the rotor. The two air bearings are symmetrically arranged to further improve the dynamic performance of the magnetic steel on both sides of the axis.
[0010] The first transverse air channel and the second transverse air channel are circular cylindrical structures, and the first vertical air channel and the second vertical air channel are annular structures.
[0011] The first thrust plate and the fourth shaft segment are positioned and connected by a first limiting pin, thereby ensuring the connection performance between the first thrust plate and the fourth shaft segment, and further preventing the first thrust plate and the fourth shaft segment from being displaced in the circumferential direction relative to each other. The second thrust plate and the seventh shaft segment are positioned and connected by a second limiting pin, thereby ensuring the connection performance between the second thrust plate and the seventh shaft segment, and further preventing the second thrust plate and the seventh shaft segment from being displaced in the circumferential direction relative to each other.
[0012] A gap adjustment gasket is provided between the second thrust plate and the seventh shaft segment, which is used to adjust the overall gap value of the first vertical air duct and the second vertical air duct on both sides of the symmetrical permanent magnet motor rotor to facilitate assembly.
[0013] The first thrust plate and the second thrust plate are both provided with annular weight-removing surfaces on their outer sides, and the dynamic balancing performance of both sides of the magnetic steel is further improved through the dynamic balancing process.
[0014] By adopting the above technical solution, the symmetrical permanent magnet motor rotor of the centrifugal compressor improves the dynamic performance of the rotor through the symmetrical arrangement of the first air bearing, the second air bearing and the airway structure thereof.
[0015] The technical effects of the utility model are:
[0016] 1. The rotor structure of the utility model adopts a symmetrical structural layout, so that the shape and size center of the rotor basically coincide with the center of gravity, and the radial gravity load of the rotor received by the first air bearing and the second air bearing is basically equal.
[0017] 2. The first thrust plate, the second thrust plate and the first air bearing, the second air bearing have the same dimensions and structure, and the two parts are completely interchangeable and universal in assembly; at the same time, the first thrust plate, the second thrust plate and the first air bearing, the second air bearing are symmetrically arranged on both sides of the center line of the magnetic steel, ensuring that the rotor composite force of the first air bearing and the second air bearing is basically close.
[0018] 3. The balancing screws and balancing weight-removing rings on both sides of the rotor are symmetrically arranged, which is conducive to the execution of the rotor dynamic balancing process, improves the dynamic balancing accuracy of the rotor, and ensures the stability of the rotor operation. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0020] FIG1 is a schematic cross-sectional view of a symmetrical permanent magnet motor rotor of a centrifugal compressor of the utility model;
[0021] FIG. 2 is a schematic diagram of a partial three-dimensional structure of a symmetrical permanent magnet motor rotor of a centrifugal compressor of the utility model. DETAILED DESCRIPTION
[0022] The following is a clear and complete description of the technical solutions in the embodiments of the utility model in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the utility model.
[0023] like Figure 1-2As shown, a symmetrical permanent magnet motor rotor of a centrifugal compressor includes a magnetic steel 6, wherein a first shaft section and a second shaft section are respectively provided on both axial sides of the magnetic steel 6, and the magnetic steel 6 is radially covered with a sleeve 5, the first shaft section includes a third shaft section 19, a fourth shaft section 92, and a fifth shaft section 81 with different outer diameters, the fifth shaft section 81 is radially connected to the sleeve 5, the outer periphery of the fourth shaft section 92 is sleeved with a first air bearing 9, the outer periphery of the third shaft section 19 is sleeved with a first thrust plate 10, a first air passage for suspending the first thrust plate 10, the first air bearing 9 and the fourth shaft section 92 are provided between the first thrust plate 10, the first air bearing 9 and the fourth shaft section 92, the second shaft section includes a sixth shaft section 82, a seventh shaft section 45, and an eighth shaft section 46 with different outer diameters, the sixth shaft section 82 is radially connected to the sleeve 5, the outer periphery of the seventh shaft section 45 is sleeved with a second air bearing 3, the outer periphery of the eighth shaft section 46 is sleeved with a second thrust plate 1, and a second air passage for suspending the second air bearing 3 is provided between the second thrust plate 1, the second air bearing 3 and the seventh shaft section 45.
[0024] In order to further improve the dynamic balance performance on both sides of the magnetic steel axis, the fourth shaft segment 92 and the fifth shaft segment 81 are connected by a first inclined surface 8, and the first inclined surface 8 is provided with a first balancing screw 7; the sixth shaft segment 82 and the seventh shaft segment 45 are connected by a second inclined surface 40, and the second inclined surface 40 is provided with a second balancing screw 14.
[0025] In order to achieve symmetry and dynamic balance of the devices on both sides of the axial direction of the magnetic steel 6, the spacing A2 between the first balancing screw 7 and the center line 61 of the magnetic steel 6 is equal to the spacing A1 between the second balancing screw 14 and the center line 61 of the magnetic steel 6. The spacing B2 between the center line 91 of the first air bearing 9 and the center line 61 of the magnetic steel 6 is equal to the spacing B1 between the center line 31 of the second air bearing 3 and the center line 61 of the magnetic steel 6. The spacing C2 between the first thrust plate 10 and the center line 61 of the magnetic steel 6 is equal to the spacing C1 between the second thrust plate 1 and the center line 61 of the magnetic steel 6.
[0026] As a preferred structure, the first air channel includes a first vertical air channel 12 and a first transverse air channel 13 which are interconnected, the first vertical air channel 12 is arranged between the first thrust plate 10 and the first air bearing 9, the first transverse air channel 13 is arranged between the fourth shaft section 92 and the first air bearing 9, and the second air channel includes a second vertical air channel 16 and a second transverse air channel 15 which are interconnected, the second vertical air channel 16 is arranged between the second thrust plate 1 and the second air bearing 3, and the second transverse air channel 15 is arranged between the seventh shaft section 45 and the second air bearing 3. The transverse and vertical air channel structures formed by the first air channel and the second air channel are used to support the radial load and axial load of the rotor, further improving the running stability of the rotor.
[0027] In order to improve the connection performance and the clearance adjustment function, the first thrust plate 10 is connected to the fourth shaft segment 92 by the first limit pin 11, and the installation position between the two is relatively fixed. The second thrust plate 1 is connected to the seventh shaft segment 45 by the second limit pin 2, and the installation position between the two is relatively fixed. A clearance adjustment gasket 17 is provided between the second thrust plate 1 and the seventh shaft segment 45. The outer sides of the first thrust plate 10 and the second thrust plate 1 are both provided with an annular weight-removing surface 20, and the dynamic balancing accuracy of the rotor is further improved by reducing weight on the annular weight-removing surface.
[0028] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A symmetrical permanent magnet motor rotor for a centrifugal compressor, comprising a magnetic steel (6), wherein a first shaft section and a second shaft section are respectively provided on both axial sides of the magnetic steel (6), and the magnetic steel (6) is radially covered with a sheath (5), characterized in that: The first shaft section comprises a third shaft section (19), a fourth shaft section (92), and a fifth shaft section (81) with different outer diameters; the fifth shaft section (81) is radially connected to a sleeve (5); the outer periphery of the fourth shaft section (92) is sleeved with a first air bearing (9); the outer periphery of the third shaft section (19) is sleeved with a first thrust plate (10); a first air passage for suspending the first air bearing (9) is provided between the first thrust plate (10), the first air bearing (9), and the fourth shaft section (92); the second shaft section comprises a sixth shaft section (82), a seventh shaft section (45), and an eighth shaft section (46) with different outer diameters; the sixth shaft section (82) is radially connected to a sleeve (5); the outer periphery of the seventh shaft section (45) is sleeved with a second air bearing (3); the outer periphery of the eighth shaft section (46) is sleeved with a second thrust plate (1); a second air passage for suspending the second air bearing (3) is provided between the second thrust plate (1), the second air bearing (3), and the seventh shaft section (45).
2. The symmetrical permanent magnet motor rotor of a centrifugal compressor according to claim 1, characterized in that: The fourth shaft segment (92) and the fifth shaft segment (81) are connected by a first inclined surface (8), and the first inclined surface (8) is provided with a first balancing screw (7). The sixth shaft segment (82) and the seventh shaft segment (45) are connected by a second inclined surface (40), and the second inclined surface (40) is provided with a second balancing screw (14).
3. The symmetrical permanent magnet motor rotor of a centrifugal compressor according to claim 2, characterized in that: The distance (A2) between the first balancing screw (7) and the center line (61) of the magnetic steel (6) is equal to the distance (A1) between the second balancing screw (14) and the center line (61) of the magnetic steel (6).
4. The symmetrical permanent magnet motor rotor of a centrifugal compressor according to claim 1, characterized in that: The distance (B2) between the center line (91) of the first air bearing (9) and the center line (61) of the magnetic steel (6) is equal to the distance (B1) between the center line (31) of the second air bearing (3) and the center line (61) of the magnetic steel (6).
5. The symmetrical permanent magnet motor rotor of a centrifugal compressor according to claim 1, characterized in that: The distance (C2) between the first thrust plate (10) and the center line (61) of the magnetic steel (6) is equal to the distance (C1) between the second thrust plate (1) and the center line (61) of the magnetic steel (6).
6. The symmetrical permanent magnet motor rotor of a centrifugal compressor according to claim 1, characterized in that: The first air channel comprises a first vertical air channel (12) and a first transverse air channel (13) which are interconnected, the first vertical air channel (12) being arranged between the first thrust plate (10) and the first air bearing (9), the first transverse air channel (13) being arranged between the fourth shaft section (92) and the first air bearing (9), and the second air channel comprises a second vertical air channel (16) and a second transverse air channel (15) which are interconnected, the second vertical air channel (16) being arranged between the second thrust plate (1) and the second air bearing (3), and the second transverse air channel (15) being arranged between the seventh shaft section (45) and the second air bearing (3).
7. The symmetrical permanent magnet motor rotor of a centrifugal compressor according to claim 1, characterized in that: The first thrust plate (10) and the fourth shaft segment (92) are connected via a first limiting pin (11), and the second thrust plate (1) and the seventh shaft segment (45) are connected via a second limiting pin (2).
8. The symmetrical permanent magnet motor rotor of a centrifugal compressor according to claim 1, characterized in that: A clearance adjustment gasket (17) is provided between the second thrust plate (1) and the seventh shaft segment (45).
9. The symmetrical permanent magnet motor rotor of a centrifugal compressor according to claim 1, characterized in that: The first thrust plate (10) and the second thrust plate (1) are both provided with an annular weight-removing surface (20) on their outer sides.