Anti-surge two-stage centrifugal compression motor structure

Abstract

The invention relates to an anti-surge two-stage centrifugal compression motor structure which is characterized by comprising a motor shaft, a pivotal bearing, an extrusion oil film damper, an impeller, an adapter disc and an anti-surge volute. The horn-shaped air guide hole structure with the gradually-reduced diameter is arranged at the air inlet of the volute, irreversible conversion from speed energy and pressure energy to internal energy is reduced, the mixing loss is reduced, and the volute connecting efficiency is improved; due to the arrangement of the air guide holes, the flow of the impeller of the compressor is expanded, and surge and blockage of the compressor are avoided; the squeezing oil film damper is arranged on the motor shaft, the squeezing oil film damper is used for buffering the vibration influence on the air compressor when surge occurs, and the service life of the air compressor is prolonged. The adopted extrusion oil film damper is designed in cooperation with the oil duct lubricating module, the extrusion oil film damper is attached to the oil duct lubricating module, and connection is compact; the chamfer structure and the arc-shaped groove are formed, so that when the surge phenomenon occurs, small space allowance can be achieved, and interference with the edge of the pivotal bearing is avoided.

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; 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

[0003] 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.

[0004] 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; 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; The air inlet of the anti-surge volute is provided with an air guide surface with a convex arc cross section, and a plurality of air guide holes are provided on the air guide surface in a circular array parallel to the axial direction of the air inlet of the anti-surge volute, and an annular air guide groove is provided on the air guide surface at the bottom end of the air guide hole, and the annular air guide groove is connected to the air guide hole; the number of the air guide holes is the same as the number of blades on the impeller, and the diameter of the air guide hole gradually decreases from the inlet to the outlet of the air guide hole to form a trumpet shape, and the diameter of the outlet end of the air guide hole is 1.2-1.5 times the width of the annular air guide groove; The squeeze film damper comprises a squirrel cage shell; the squirrel cage shell is a hollow cylindrical structure, and both ends of the squirrel cage shell are opened; a flange is arranged at the outer contour of one end of the squirrel cage shell; the middle part of the squirrel cage shell has a plurality of cage bars, and through holes are formed between adjacent cage bars; a plurality of oil return holes are evenly formed on the side wall of the other end of the squirrel cage shell; an outer arc groove is arranged at the junction of the flange and the outer contour of the squirrel cage shell, and a straight chamfer is arranged at the junction of the flange and the inner contour of the end of the squirrel cage shell; a step is arranged between the inner contour of the cage bar area on the squirrel cage shell and the inner contour of the oil return hole area on the squirrel cage shell, and an inner arc groove is arranged at the junction of the corner position of the step and the oil return hole area.

[0005] Furthermore, it also includes a bearing retainer, an oil channel lubrication module and a sealing module; The motor shaft has a stepped structure, and the outer contour of the motor shaft is provided with a first step surface, a second step surface, a third step surface and a fourth step surface in sequence from the end to the middle position; the slewing bearing is nested at the third step surface, and bearing retainers are respectively provided on both sides of the slewing bearing at the third step surface to limit the inner ring of the slewing bearing, and the bearing retainer at the third step surface and close to the second step surface extends to above the second step surface; a thread is provided on the second step surface, and a locking nut is provided on the thread, and the locking nut cooperates with the thread to realize pressing the bearing retainer and the slewing bearing on the third step surface; an inner sealing bayonet is provided on the bearing retainer at the third step surface and close to the fourth step surface; The oil return hole area of ​​the squeeze film damper is nested in the outer contour of the slewing bearing, and the cage bar area of ​​the squeeze film damper extends above the second step surface of the motor shaft; the flange of the squeeze film damper is locked on the motor end cover by bolts.

[0006] Furthermore, the oil channel lubrication module includes a radial oil channel and an axial oil channel; the radial oil channel is arranged along the radial direction of the motor end cover, and the axial oil channel is vertically arranged at one end of the radial oil channel, the radial oil channel and the axial oil channel form an L-shaped structure, and the bottom end of the axial oil channel is provided 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 connected to the motor shaft mounting hole of the motor end cover, and the first oil inlet is located at the outer ring of the slewing bearing on the motor end cover, and the second oil inlet is located beside the slewing bearing on the motor end cover.

[0007] Further, 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 accommodating 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 step surface of the motor shaft; the outer sealing bayonet is located on the inner side of the through hole of the outer annular sealing cover; the outer pressure ring is arranged at the first step surface of the motor shaft, the outer pressure ring and the outer sealing bayonet form an annular 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 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 circular hole for accommodating the motor shaft to pass through is opened at the center of the inner annular sealing cover; the circular hole contour of the inner annular sealing cover is embedded in the inner sealing bayonet; 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 are both provided with a plurality of oil storage tanks.

[0008] Furthermore, a plurality of oil storage tanks are provided on the inner side wall of the guide hole of the adapter plate.

[0009] The advantages of the present invention are: 1) In the present invention, a trumpet-shaped air guide hole structure with a gradually decreasing diameter is provided at the air inlet of the volute, so that the air flow velocity at the output end of the air guide hole is increased, and a velocity gradient with the air flow velocity on the outer side of the impeller is avoided, the shearing effect between the air flow micro-clusters is reduced, and the irreversible conversion of velocity energy and pressure energy to internal energy is reduced, the mixing loss is reduced, and the efficiency of the volute connection is improved; at the same time, the setting of the air guide hole of the structure widens the flow of the compressor impeller, avoids the occurrence of compressor surge and blockage, and is particularly suitable for anti-surge of small centrifugal compressors.

[0010] 2) In the present invention, a squeeze film damper is also arranged on the motor shaft, and the squeeze film damper is used to buffer the vibration impact on the air compressor when surge occurs, thereby improving the service life of the air compressor; in addition, the squeeze film damper is designed in conjunction with the oil channel lubrication module, and can be well installed on the end face of the motor end cover, while fitting the oil channel lubrication module and being compactly connected; the chamfered structure and arc-shaped groove can have a smaller space margin when surge occurs, thereby avoiding interference with the edge of the slewing bearing and improving the service life of the squeeze film damper. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0012] Figure 1 This is a structural diagram of an anti-surge two-stage centrifugal compression motor of the present invention.

[0013] Figure 2 This is a partial enlarged view of an anti-surge two-stage centrifugal compression motor of the present invention.

[0014] Figure 3 The present invention is a structural diagram of a squeeze film damper for an anti-surge two-stage centrifugal compression motor. DETAILED DESCRIPTION

[0015] In order to make the purpose, 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 part of the embodiments of the present invention, not all of the embodiments. Generally, 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.

[0016] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] like Figures 1 to 3 The structure of an anti-surge two-stage centrifugal compression motor shown in the figure includes a motor housing 1 and a motor end cover 2, wherein the motor end cover 2 is arranged at the end of the motor housing 1 by bolt connection, and a motor shaft mounting hole is opened at the center of the motor housing 1; it also includes a motor shaft 3, a slewing bearing 4, a squeeze film damper 5, an impeller 6, an adapter plate 7 and an anti-surge volute 8.

[0018] The outer contour of the end of the motor shaft 3 is installed at the motor shaft mounting hole position of the motor end cover 2 through the slewing bearing 4; a connecting hole is provided at the end of the motor shaft 3, and the end of the motor shaft 3 is connected to the impeller 6 by bolts, and an anti-surge volute 8 is provided on the outer side of the impeller 6, the inner end face of the anti-surge volute 8 is connected to the adapter plate 7 by bolts, and the adapter plate 7 is fixed to the outer end face of the motor end cover 2 by bolts.

[0019] An air guide surface with a convex arc cross-section is provided at the air inlet of the anti-surge volute 8, and a plurality of air guide holes 81 are provided on the air guide surface in a circular array parallel to the axial direction of the air inlet of the anti-surge volute 8, and an annular air guide groove 82 is provided on the air guide surface at the bottom end of the air guide hole 81, and the annular air guide groove 82 is connected to the air guide hole 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 hole 81 gradually decreases from the inlet to the outlet of the air guide hole 81 to form a trumpet shape, and the diameter of the outlet end of the air guide hole 81 is 1.2-1.5 times the width of the annular air guide groove 82.

[0020] The squeeze film damper 5 comprises a squirrel cage shell; the squirrel cage shell is a hollow cylindrical structure, and both ends of the squirrel cage shell are opened; a flange 51 is arranged at the outer contour of one end of the squirrel cage shell; the middle part of the squirrel cage shell has a plurality of cage bars 52, and through holes are formed between adjacent cage bars 52; a plurality of oil return holes 53 are evenly opened on the side wall of the other end of the squirrel cage shell; an outer arc groove is arranged at the junction of the flange 51 and the outer contour of the squirrel cage shell, and a straight chamfer is arranged at the junction of the flange 51 and the inner contour of the end of the squirrel cage shell; a step is arranged between the inner contour of the cage bar area on the squirrel cage shell and the inner contour of the oil return hole area on the squirrel cage shell, and an inner arc groove is arranged at the junction of the corner position of the step and the oil return hole area.

[0021] It also includes a bearing retainer 9, an oil channel lubrication module 10 and a sealing module 11; The motor shaft 3 has a stepped structure, and the outer contour of the motor shaft 3 is provided with a first step surface 31, a second step surface 32, a third step surface 33 and a fourth step surface 34 in sequence from the end to the middle position; the slewing bearing 4 is nested in the third step surface 33, and bearing retainers 9 are respectively provided on both sides of the slewing bearing 4 at the third step surface 33 to limit the inner ring of the slewing bearing 4, and the bearing retainer 9 at the third step surface 33 and close to the second step surface 32 extends to above the second step surface 32; a thread is provided on the second step surface 32, and a locking nut is provided on the thread, and the locking nut cooperates with the thread to realize pressing the bearing retainer 9 and the slewing bearing 4 on the third step surface 33; an inner sealing bayonet 91 is provided on the bearing retainer 9 at the third step surface 33 and close to the fourth step surface 34.

[0022] The oil return hole area of ​​the squeeze film damper 5 is embedded in the outer contour of the slewing 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 fastened to the motor end cover 2 by bolts.

[0023] The oil channel lubrication module 10 includes a radial oil channel 101 and an axial oil channel 102; the radial oil channel 101 is arranged along the radial direction of the motor end cover 2, and the axial oil channel 102 is vertically arranged at one end of the radial oil channel 101, the radial oil channel 101 and the axial oil channel 102 form an L-shaped structure, and the bottom end of the axial oil channel 102 is provided 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 connected to 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 slewing bearing 4 on the motor end cover 2, and the second oil inlet 104 is located beside the slewing bearing 4 on the motor end cover 2.

[0024] 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 screwed on the outer side of the motor end cover 2, and a through hole for accommodating 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 on the inner side of 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, and the outer pressure ring 113 and the outer sealing bayonet 112 form a An annular groove is formed to accommodate the position of the through hole of the outer annular sealing cover, and the through hole contour of the outer annular sealing cover 111 is embedded in the annular 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 circular hole for accommodating the motor shaft 3 to pass through is opened at the center of the inner annular sealing cover 114; the circular hole contour of the inner annular sealing cover 114 is embedded in the inner sealing bayonet 91; 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 are both provided with a plurality of oil storage grooves; the inner side wall of the guide hole of the adapter plate 7 is provided with a plurality of oil storage grooves.

[0025] The working principle of the present invention is: by setting a trumpet-shaped air guide hole structure with a gradually reduced diameter at the air inlet of the volute, the air flow velocity at the output end of the air guide hole is increased, the velocity gradient with the air flow velocity outside the impeller is avoided, the shearing effect between the air flow micro-groups is reduced, the irreversible conversion of velocity energy and pressure energy to internal energy is reduced, the mixing loss is reduced, and the efficiency of the volute connection is improved; at the same time, the setting of the air guide hole of the structure widens the flow of the compressor impeller, avoids the occurrence of compressor surge and blockage, and is particularly suitable for anti-surge of small centrifugal compressors; In the present invention, a squeeze film damper is also arranged on the motor shaft, and the squeeze film damper is used to buffer the vibration effect on the air compressor when surge occurs, thereby improving the service life of the air compressor; in addition, the squeeze film damper is designed in conjunction with the oil channel lubrication module, and can be well installed on the end face of the motor end cover, while fitting the oil channel lubrication module and being compactly connected; the chamfered structure and the arc-shaped groove can have a smaller space margin when surge occurs, thereby avoiding interference with the edge of the slewing bearing and improving the service life of the squeeze film damper.

[0026] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A surge-proof 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; characterized in that: It also includes the motor shaft, slewing bearing, squeeze film damper, impeller, adapter plate and anti-surge volute; 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; The air inlet of the anti-surge volute is provided with an air guide surface with a convex arc cross section, and a plurality of air guide holes are provided on the air guide surface in a circular array parallel to the axial direction of the air inlet of the anti-surge volute, and an annular air guide groove is provided on the air guide surface at the bottom end of the air guide hole, and the annular air guide groove is connected to the air guide hole; the number of the air guide holes is the same as the number of blades on the impeller, and the diameter of the air guide hole gradually decreases from the inlet to the outlet of the air guide hole to form a trumpet shape, and the diameter of the outlet end of the air guide hole is 1.2-1.5 times the width of the annular air guide groove; The squeeze film damper comprises a squirrel cage shell; the squirrel cage shell is a hollow cylindrical structure, and both ends of the squirrel cage shell are opened; a flange is arranged at the outer contour of one end of the squirrel cage shell; the middle part of the squirrel cage shell has a plurality of cage bars, and through holes are formed between adjacent cage bars; a plurality of oil return holes are evenly formed on the side wall of the other end of the squirrel cage shell; an outer arc groove is arranged at the junction of the flange and the outer contour of the squirrel cage shell, and a straight chamfer is arranged at the junction of the flange and the inner contour of the end of the squirrel cage shell; a step is arranged between the inner contour of the cage bar area on the squirrel cage shell and the inner contour of the oil return hole area on the squirrel cage shell, and an inner arc groove is arranged at the junction of the corner position of the step and the oil return hole area.

2. The anti-surge two-stage centrifugal compressor motor structure according to claim 1, characterized in that: It also includes a bearing cage, an oil channel lubrication module and a sealing module; The motor shaft has a stepped structure, and the outer contour of the motor shaft is provided with a first step surface, a second step surface, a third step surface and a fourth step surface in sequence from the end to the middle position; the slewing bearing is nested at the third step surface, and bearing retainers are respectively provided on both sides of the slewing bearing at the third step surface to limit the inner ring of the slewing bearing, and the bearing retainer at the third step surface and close to the second step surface extends to above the second step surface; a thread is provided on the second step surface, and a locking nut is provided on the thread, and the locking nut cooperates with the thread to realize pressing the bearing retainer and the slewing bearing on the third step surface; an inner sealing bayonet is provided on the bearing retainer at the third step surface and close to the fourth step surface; The oil return hole area of ​​the squeeze film damper is nested in the outer contour of the slewing bearing, and the cage bar area of ​​the squeeze film damper extends above the second step surface of the motor shaft; the flange of the squeeze film damper is locked on the motor end cover by bolts.

3. The anti-surge two-stage centrifugal compressor motor structure according to claim 2, characterized in that: The oil channel lubrication module includes a radial oil channel and an axial oil channel; the radial oil channel is arranged along the radial direction of the motor end cover, and the axial oil channel is vertically arranged at one end of the radial oil channel, the radial oil channel and the axial oil channel form an L-shaped structure, and the bottom end of the axial oil channel is provided 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 connected to the motor shaft mounting hole of the motor end cover, and the first oil inlet is located at the outer ring of the slewing bearing on the motor end cover, and the second oil inlet is located beside the slewing bearing on the motor end cover.

4. The anti-surge two-stage centrifugal compressor motor structure according to claim 2, characterized in that: The sealing module comprises an outer sealing unit and an inner sealing unit; the outer sealing unit comprises 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 accommodating 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 on the inner side of the through hole of the outer annular sealing cover; the outer pressure ring is arranged at the first stepped surface of the motor shaft, the outer pressure ring and the outer sealing bayonet form an annular 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 groove; the inner sealing unit comprises 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 circular hole for accommodating the motor shaft to pass through is opened at the center of the inner annular sealing cover; the circular hole contour of the inner annular sealing cover is embedded in the inner sealing bayonet; 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 are both provided with a plurality of oil storage tanks.

5. The anti-surge two-stage centrifugal compressor motor structure 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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