A two-stage centrifugal compressor motor structure for anti-surge

Abstract

The present invention relates to an anti-surge two-stage centrifugal compressor motor structure, which is characterized in that: it includes a motor shaft, a rotary bearing, an squeeze film damper, an impeller, an adapter plate and an anti-surge volute; a wind guiding hole structure with a gradually reducing diameter in a trumpet shape is arranged at the air inlet of the volute, which reduces the irreversible conversion of velocity energy and pressure energy into internal energy, reduces mixing loss, and improves the efficiency of the volute connection; the setting of the wind guiding holes in this structure broadens the flow rate of the compressor impeller, avoiding the occurrence of compressor surge and blockage; an squeeze film damper is arranged on the motor shaft, and the squeeze film damper is used to buffer the vibration impact on the air compressor when surge occurs, improving the service life of the air compressor; the adopted squeeze film damper is designed in cooperation with the oil passage lubrication module, fitting the oil passage lubrication module and having a compact connection; the chamfer structure and arc-shaped groove are opened, which can have a small space margin when the surge phenomenon occurs, avoiding interference with the edge of the rotary bearing.

Description

Technical Field

[0001] The invention relates to the technical field of air compressors, and in particular to an anti-surge two-stage centrifugal compression motor structure. Background Art

[0002] Due to the aerodynamic characteristics of the air compressor itself, when the air volume decreases to a certain extent and the inlet and outlet pressures reach the surge pressure ratio, the air compressor will experience surge. From the current technical understanding, the surge phenomenon of the air compressor will cause serious deterioration of the performance of the air compressor and produce abnormal noise; moreover, the surge phenomenon will generally directly lead to violent vibration of the air compressor, seriously shortening the service life of the air compressor and even causing the blades of the air compressor to break. Therefore, in the current air compressor use specifications, it is strictly forbidden for air compressors to operate in the surge zone;

[0003] In order to avoid the occurrence of air compressor surge as much as possible, there are some air compressors with anti-surge devices on the market. At the same time, some manufacturers have reduced the frequency of fan surge by installing anti-surge devices on air compressors. In general, although these anti-surge devices have played a certain anti-surge role, their structures are relatively complex. For processing companies, the overall material and processing costs have increased significantly compared with the past. Therefore, the overall application benefits of such existing anti-surge devices are not ideal and still need to be further optimized. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an anti-surge two-stage centrifugal compressor motor structure, which can solve the problem that the traditional two-stage centrifugal compressor motor has poor anti-surge effect and poor shock absorption effect when surge occurs.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: an anti-surge two-stage centrifugal compression motor structure, comprising a motor housing and a motor end cover, wherein the motor end cover is arranged at the end of the motor housing by bolt connection, and a motor shaft mounting hole is opened at the center of the motor housing; its innovation lies in: further comprising a motor shaft, a slewing bearing, a squeeze film damper, an impeller, a transfer plate and an anti-surge volute;

[0006] The outer contour of the end of the motor shaft is mounted at the motor shaft mounting hole position of the motor end cover through a slewing bearing; a connecting hole is provided at the end of the motor shaft, and the end of the motor shaft is connected to an impeller through bolts, and an anti-surge volute is provided on the outer side of the impeller, and the inner side end surface of the anti-surge volute is connected to the adapter plate through bolts, and the adapter plate is fixed to the outer side end surface of the motor end cover through bolts;

[0007] An air inlet of the anti-surge volute is provided with a wind guiding surface having a convex arc-shaped cross section. A plurality of wind guiding holes are arranged in an annular array on the wind guiding surface in a direction parallel to the axis of the air inlet of the anti-surge volute. An annular wind guiding groove is arranged on the wind guiding surface at the bottom end of the wind guiding hole, and the annular wind guiding groove is communicated with the wind guiding hole. The number of the wind guiding holes is the same as the number of blades on the impeller. The diameter of the wind guiding hole gradually decreases from the inlet to the outlet of the wind guiding hole to form a trumpet shape, and the diameter of the outlet end of the wind guiding hole is 1.2-1.5 times the width of the annular wind guiding groove.

[0008] The squeeze film damper includes a squirrel cage housing. The squirrel cage housing is a hollow cylindrical structure with both ends open. A flange is arranged at the outer contour of one end of the squirrel cage housing. The middle part of the squirrel cage housing has a plurality of cage bars, and through holes are provided between adjacent cage bars. A plurality of oil return holes are evenly formed in the side wall at the other end of the squirrel cage housing. An outer arc-shaped groove is arranged at the connection between the flange and the outer contour of the squirrel cage housing, and a straight chamfer is arranged at the connection between the flange and the inner contour of the end of the squirrel cage housing. A step is arranged between the inner contour of the cage bar area and the inner contour of the oil return hole area on the squirrel cage housing, and an inner arc-shaped groove is arranged at the connection between the corner position of the step and the oil return hole area.

[0009] Further, it further includes a bearing cage, an oil passage lubrication module and a sealing module.

[0010] The motor shaft has a stepped structure, and the outer contour of the motor shaft is sequentially provided with a first stepped surface, a second stepped surface, a third stepped surface and a fourth stepped surface from the end to the middle position. The slewing bearing is nested at the third stepped surface, and bearing cages are respectively arranged on both sides of the slewing bearing at the third stepped surface to limit the inner ring of the slewing bearing. The bearing cage at the third stepped surface and close to the second stepped surface extends above the second stepped surface. Threads are arranged on the second stepped surface, and a locking nut is arranged on the threads. The locking nut is matched with the threads to press the bearing cage and the slewing bearing on the third stepped surface. An inner sealing bayonet is arranged on the bearing cage at the third stepped surface and close to the fourth stepped surface.

[0011] The oil return hole area of the squeeze film damper is nested on the outer contour of the slewing bearing, and the cage bar area of the squeeze film damper extends above the second stepped surface of the motor shaft. The flange of the squeeze film damper is locked on the motor end cover by bolts.

[0012] Furthermore, the oil passage lubrication module includes a radial oil passage and an axial oil passage; the radial oil passage is arranged along the radial direction of the motor end cover, the axial oil passage is vertically arranged at one end of the radial oil passage, the radial oil passage and the axial oil passage form an L-shaped structure, and the bottom end of the axial oil passage is distributed with a first oil inlet and a second oil inlet along the axis of the motor end cover; the first oil inlet and the second oil inlet are communicated with the motor shaft mounting hole of the motor end cover, and the first oil inlet is located at the outer ring of the rotary bearing on the motor end cover, and the second oil inlet is located beside the rotary bearing on the motor end cover.

[0013] Furthermore, the sealing module includes an outer sealing unit and an inner sealing unit; the outer sealing unit includes an outer annular sealing cover, an outer sealing bayonet and an outer pressure ring; the outer annular sealing cover is locked on the outer side surface of the motor end cover by screws, and a through hole for the motor shaft to pass through is opened at the center of the outer annular sealing cover; the outer sealing bayonet is arranged at the first stepped surface of the motor shaft; the outer sealing bayonet is located inside the through hole of the outer annular sealing cover; the outer pressure ring is arranged at the first stepped surface of the motor shaft, and the outer pressure ring and the outer sealing bayonet form an annular clamping groove for accommodating the position of the through hole of the outer annular sealing cover, and the through hole contour of the outer annular sealing cover is embedded in the annular clamping groove; the inner sealing unit includes an inner annular sealing cover; the inner annular sealing cover is locked on the inner side surface of the motor end cover by screws, and a round hole for the motor shaft to pass through is opened at the center of the inner annular sealing cover; the round hole contour of the inner annular sealing cover is embedded in the inner sealing bayonet; a plurality of oil storage grooves are arranged on the inner side wall of the shaft hole of the outer annular sealing cover and the inner side wall of the shaft hole of the inner annular sealing cover.

[0014] Furthermore, a plurality of oil storage grooves are arranged on the inner side wall of the guide hole of the adapter plate.

[0015] The advantages of the present invention are as follows:

[0016] 1) In the present invention, by arranging a wind guiding hole structure with a gradually decreasing diameter in a trumpet shape at the air inlet of the volute, the air flow velocity at the output end of the wind guiding hole is increased, avoiding the generation of a velocity gradient with the air flow velocity outside the impeller, reducing the shear action between air flow microgroups, reducing the irreversible conversion of velocity energy and pressure energy into internal energy, reducing mixing loss, and improving the efficiency of the volute connection; at the same time, the arrangement of the wind guiding holes of this structure broadens the flow rate of the compressor impeller, avoiding the occurrence of compressor surge and blockage, and is particularly suitable for anti-surge of small centrifugal compressors.

[0017] 2) In the present invention, an squeeze film damper is simultaneously arranged on the motor shaft, and the squeeze film damper is used to buffer the vibration impact on the air compressor when surging occurs, thereby prolonging the service life of the air compressor. In addition, the adopted squeeze film damper is designed in cooperation with the oil passage lubrication module, can be well installed on the end face of the motor end cover, and at the same time fits the oil passage lubrication module with a compact connection. The provided chamfer structure and arc-shaped groove can have a small space margin when surging occurs, avoiding interference with the edge of the rotary bearing and improving the service life of the squeeze film damper. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0019] Figure 1 It is a structural diagram of an anti-surge two-stage centrifugal compression motor of the present invention.

[0020] Figure 2 It is a partially enlarged view of an anti-surge two-stage centrifugal compression motor of the present invention.

[0021] Figure 3 It is a structural diagram of the squeeze film damper of an anti-surge two-stage centrifugal compression motor of the present invention. SPECIFIC EMBODIMENTS

[0022] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0024] As Figures 1 to 3 shown, a structure of an anti-surge two-stage centrifugal compression motor includes a motor housing 1 and a motor end cover 2. The motor end cover 2 is arranged at the end of the motor housing 1 through bolt connection, and a motor shaft mounting hole is opened at the center of the motor housing 1. It further includes a motor shaft 3, a rotary bearing 4, a squeeze film damper 5, an impeller 6, an adapter plate 7 and an anti-surge volute 8.

[0025] The outer contour of the end of the motor shaft 3 is installed at the position of the motor shaft mounting hole of the motor end cover 2 through a slewing bearing 4; a connection hole is provided at the end of the motor shaft 3, and the end of the motor shaft 3 is bolted to an impeller 6, and an anti-surge volute 8 is provided outside the impeller 6. The inner end face of the anti-surge volute 8 is bolted to an adapter plate 7, and the adapter plate 7 is fixed to the outer end face of the motor end cover 2 by bolts.

[0026] At the air inlet of the anti-surge volute 8, a guide wind surface with a convex arc-shaped cross-section is provided, and a plurality of air guide holes 81 are arranged in an annular array parallel to the axis direction of the air inlet of the anti-surge volute 8 on the guide wind surface. At the bottom end of the air guide holes 81, an annular air guide groove 82 is provided on the guide wind surface, and the annular air guide groove 82 is communicated with the air guide holes 81; the number of the air guide holes 81 is the same as the number of blades on the impeller 6, and the diameter of the air guide holes 81 gradually decreases from the inlet to the outlet direction of the air guide holes 81 to form a trumpet shape, and the diameter of the outlet end of the air guide holes 81 is 1.2 - 1.5 times the width of the annular air guide groove 82.

[0027] The squeeze film damper 5 includes a squirrel cage housing; the squirrel cage housing is a hollow cylindrical structure, and both ends of the squirrel cage housing are open; a flange 51 is provided at the outer contour of one end of the squirrel cage housing; a plurality of cage bars 52 are provided in the middle part of the squirrel cage housing, and through holes are provided between adjacent cage bars 52; a plurality of oil return holes 53 are evenly opened on the side wall at the other end of the squirrel cage housing; an outer arc-shaped groove is provided at the connection between the flange 51 and the outer contour of the squirrel cage housing, and a straight chamfer is provided at the connection between the flange 51 and the inner contour of the end of the squirrel cage housing; a step is provided between the inner contour of the cage bar area and the inner contour of the oil return hole area on the squirrel cage housing, and an inner arc-shaped groove is provided at the connection between the corner position of the step and the oil return hole area.

[0028] It further includes a bearing cage 9, an oil passage lubrication module 10 and a sealing module 11;

[0029] The motor shaft 3 has a stepped structure, and the outer contour of the motor shaft 3 is sequentially provided with a first stepped surface 31, a second stepped surface 32, a third stepped surface 33 and a fourth stepped surface 34 from the end to the middle position; the slewing bearing 4 is nested at the third stepped surface 33, and bearing cages 9 are respectively provided on both sides of the slewing bearing 4 at the third stepped surface 33 to limit the inner ring of the slewing bearing 4. The bearing cage 9 close to the second stepped surface 32 at the third stepped surface 33 extends above the second stepped surface 32; threads are provided on the second stepped surface 32, and a locking nut is provided on the threads. The locking nut cooperates with the threads to press the bearing cage 9 and the slewing bearing 4 against the third stepped surface 33; an inner sealing bayonet 91 is provided on the bearing cage 9 close to the fourth stepped surface 34 at the third stepped surface 33.

[0030] The oil return hole area of the squeeze film damper 5 is nested in the outer contour of the rotary bearing, and the cage bar area of the squeeze film damper extends above the second step surface 32 of the motor shaft 3; the flange 51 of the squeeze film damper 5 is locked to the motor end cover 2 by bolts.

[0031] The oil passage lubrication module 10 includes a radial oil passage 101 and an axial oil passage 102; the radial oil passage 101 is arranged along the radial direction of the motor end cover 2, the axial oil passage 102 is vertically arranged at one end of the radial oil passage 101, the radial oil passage 101 and the axial oil passage 102 form an L-shaped structure, and the bottom end of the axial oil passage 102 is distributed with a first oil inlet 103 and a second oil inlet 104 along the axis of the motor end cover 2; the first oil inlet 103 and the second oil inlet 104 are communicated with the motor shaft mounting hole of the motor end cover 2, and the first oil inlet 103 is located at the outer ring of the rotary bearing 4 on the motor end cover 2, and the second oil inlet 104 is located beside the rotary bearing 4 on the motor end cover 2.

[0032] The sealing module 11 includes an outer sealing unit and an inner sealing unit; the outer sealing unit includes an outer annular sealing cover 111, an outer sealing bayonet 112 and an outer pressure ring 113; the outer annular sealing cover 111 is locked to the outer side surface of the motor end cover 2 by screws, and a through hole for the motor shaft 3 to pass through is opened at the center of the outer annular sealing cover 111; the outer sealing bayonet 112 is arranged at the first step surface 31 of the motor shaft 3; the outer sealing bayonet 112 is located inside the through hole of the outer annular sealing cover 111; the outer pressure ring 113 is arranged at the first step surface 31 of the motor shaft 3, the outer pressure ring 113 and the outer sealing bayonet 112 form an annular clamping groove for accommodating the through hole position of the outer annular sealing cover, and the through hole contour of the outer annular sealing cover 111 is embedded in the annular clamping groove; the inner sealing unit includes an inner annular sealing cover 114; the inner annular sealing cover 114 is locked to the inner side surface of the motor end cover 2 by screws, and a round hole for the motor shaft 3 to pass through is opened at the center of the inner annular sealing cover 114; the round hole contour of the inner annular sealing cover 114 is embedded in the inner sealing bayonet 91; a plurality of oil storage grooves are arranged on the inner side wall of the shaft hole of the outer annular sealing cover 111 and the inner side wall of the shaft hole of the inner annular sealing cover 114; a plurality of oil storage grooves are arranged on the inner side wall of the guide hole of the adapter plate 7.

[0033] The working principle of the present invention is: by arranging a wind guiding hole structure with a gradually decreasing diameter in a trumpet shape at the air inlet of the volute, the air flow velocity at the output end of the wind guiding hole is increased, avoiding the generation of a velocity gradient with the air flow velocity outside the impeller, reducing the shear action between air flow microgroups, reducing the irreversible conversion of velocity energy and pressure energy into internal energy, reducing mixing loss, and improving the efficiency of the volute connection; at the same time, the arrangement of the wind guiding hole of this structure broadens the flow rate of the compressor impeller, avoiding the occurrence of compressor surge and blockage, and is especially suitable for anti-surge of small centrifugal compressors.

[0034] In the present invention, an squeeze film damper is simultaneously arranged on the motor shaft, and the squeeze film damper is used to buffer the vibration impact on the air compressor when surging occurs, thereby improving the service life of the air compressor. In addition, the adopted squeeze film damper is designed in cooperation with an oil passage lubrication module, and can be well installed on the end face of the motor end cover while fitting the oil passage lubrication module, with a compact connection. The provided chamfer structure and arc-shaped groove can have a small space margin when surging occurs, avoiding interference with the edge of the rotary bearing and improving the service life of the squeeze film damper.

[0035] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A two-stage centrifugal compressor motor structure for anti-surge, comprising a motor housing and a motor end cover, the motor end cover is arranged at the end of the motor housing through bolt connection, and a motor shaft mounting hole is opened at the center of the motor housing; it is characterized in that: It also includes a motor shaft, a slewing bearing, an oil squeeze film damper, an impeller, an adapter plate, and an anti-surge volute; The outer contour of the end of the motor shaft is installed at the motor shaft mounting hole position of the motor end cover through the slewing bearing; a connection hole is provided at the end of the motor shaft, and the end of the motor shaft is bolted to the impeller, and an anti-surge volute is arranged outside the impeller. The inner end face of the anti-surge volute is bolted to the adapter plate, and the adapter plate is fixed to the outer end face of the motor end cover by bolts; A wind guiding surface with a convex arc cross-section is provided at the air inlet of the anti-surge volute, and a number of wind guiding holes are arranged in an annular array parallel to the axis direction of the air inlet of the anti-surge volute on the wind guiding surface. And at the bottom end of the wind guiding hole, a ring-shaped wind guiding groove is arranged on the wind guiding surface, and the ring-shaped wind guiding groove is communicated with the wind guiding hole; the number of the wind guiding holes is the same as the number of blades on the impeller, and the diameter of the wind guiding hole gradually decreases from the inlet to the outlet direction of the wind guiding hole to form a horn shape, and the diameter of the outlet end of the wind guiding hole is 1.2 - 1.5 times the width of the ring-shaped wind guiding groove; The oil squeeze film damper includes a squirrel cage housing; the squirrel cage housing is a hollow cylindrical structure, and both ends of the squirrel cage housing are open; a flange is arranged at the outer contour of one end of the squirrel cage housing; a number of cage bars are provided in the middle part of the squirrel cage housing, and through holes are provided between adjacent cage bars; a number of oil return holes are evenly opened on the side wall at the other end of the squirrel cage housing; an outer arc-shaped groove is arranged at the connection between the flange and the outer contour of the squirrel cage housing, and a straight chamfer is arranged at the connection between the flange and the inner contour of the end of the squirrel cage housing; a step is arranged between the inner contour of the cage bar area and the inner contour of the oil return hole area on the squirrel cage housing, and an inner arc-shaped groove is arranged at the connection between the corner position of the step and the oil return hole area; It also includes a bearing cage, an oil passage lubrication module, and a sealing module; The motor shaft has a stepped structure, and the outer contour of the motor shaft is successively provided with a first stepped surface, a second stepped surface, a third stepped surface, and a fourth stepped surface from the end to the middle position; the slewing bearing is nested at the third stepped surface, and bearing cages are respectively arranged on both sides of the slewing bearing at the third stepped surface to limit the inner ring of the slewing bearing, and the bearing cage close to the second stepped surface at the third stepped surface extends above the second stepped surface; a thread is provided on the second stepped surface, and a locking nut is arranged on the thread. The locking nut cooperates with the thread to press the bearing cage and the slewing bearing on the third stepped surface; an inner sealing bayonet is arranged on the bearing cage close to the fourth stepped surface at the third stepped surface; The oil return hole area of the oil squeeze film damper is nested on the outer contour of the slewing bearing, and the cage bar area of the oil squeeze film damper extends above the second stepped surface of the motor shaft; the flange of the oil squeeze film damper is locked to the motor end cover by bolts.

2. The structure of an anti-surge two-stage centrifugal compressor motor according to claim 1, wherein: The oil passage lubrication module includes a radial oil passage and an axial oil passage; the radial oil passage is arranged along the radial direction of the motor end cover, the axial oil passage is vertically arranged at one end of the radial oil passage, the radial oil passage and the axial oil passage form an L-shaped structure, and the bottom end of the axial oil passage is distributed with a first oil inlet and a second oil inlet along the axis of the motor end cover; the first oil inlet and the second oil inlet are communicated with the motor shaft mounting hole of the motor end cover, and the first oil inlet is located at the outer ring of the rotary bearing on the motor end cover, and the second oil inlet is located beside the rotary bearing on the motor end cover.

3. The structure of a two-stage centrifugal compressor motor for anti-surge according to claim 1, wherein: The sealing module includes an outer sealing unit and an inner sealing unit; the outer sealing unit includes an outer annular sealing cover, an outer sealing bayonet and an outer pressing ring; the outer annular sealing cover is locked on the outer side surface of the motor end cover by screws, and a through hole for the motor shaft to pass through is opened at the center of the outer annular sealing cover; the outer sealing bayonet is arranged at the first stepped surface of the motor shaft; the outer sealing bayonet is located inside the through hole of the outer annular sealing cover; the outer pressing ring is arranged at the first stepped surface of the motor shaft, and the outer pressing ring and the outer sealing bayonet form an annular clamping groove for accommodating the position of the through hole of the outer annular sealing cover, and the through hole contour of the outer annular sealing cover is embedded in the annular clamping groove; the inner sealing unit includes an inner annular sealing cover; the inner annular sealing cover is locked on the inner side surface of the motor end cover by screws, and a round hole for the motor shaft to pass through is opened at the center of the inner annular sealing cover; the round hole contour of the inner annular sealing cover is embedded in the inner sealing bayonet; a plurality of oil storage grooves are arranged on the inner side wall of the shaft hole of the outer annular sealing cover and the inner side wall of the shaft hole of the inner annular sealing cover.

4. A structure of an anti-surge two-stage centrifugal compressor motor according to claim 1, characterized in that: A plurality of oil storage grooves are arranged on the inner side wall of the guide hole of the adapter plate.

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