CN219262684U

CN219262684U - Axial force balance structure and double-stage screw compressor using same

Info

Publication number: CN219262684U
Application number: CN202223265954.4U
Authority: CN
Inventors: 龙忠铿; 张治平; 张益钦; 武晓昆; 毕雨时
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2022-12-05
Filing date: 2022-12-05
Publication date: 2023-06-27
Anticipated expiration: 2032-12-05

Abstract

The utility model provides an axial force balance structure and a double-stage screw compressor applying the same, and relates to the technical field of compressors. The axial force balancing structure comprises an exhaust side bearing seat, a machine body and a rotor, wherein an oil supply hole is formed in the exhaust side bearing seat, and an air suction port is formed in the machine body; the two axial sides of the rotor are respectively provided with an exhaust side oil hole and an air suction side oil hole, the exhaust side oil hole and the air suction side oil hole are respectively communicated with the oil supply hole and the air suction port, and an internal oil way is further formed in the rotor. And a double-stage screw compressor, to which the above-described axial force balancing structure is applied. Based on the technical scheme of the utility model, the high-pressure application range of the compressor can be widened, the number of axial bearings can be reduced, the compressor structure is compact, the cost of the compressor is saved, the power consumption of the compressor oil pump is reduced, and the working efficiency of the compressor is improved.

Description

Axial force balance structure and double-stage screw compressor using same

Technical Field

The utility model relates to the technical field of compressors, in particular to an axial force balancing structure and a double-stage screw compressor using the same.

Background

The screw compressor has wide application in various fields due to the advantages of simple structure, high reliability, capability of carrying liquid and mixing transportation, and the like. In order to improve the applicable pressure range of the double-screw compressor, a single-machine double-stage screw compressor and the latest coaxial direct-drive double-stage screw compressor (coaxial direct drive refers to that two stages of screw rotors share a main shaft, linkage is realized through the main shaft, and a cylindrical roller bearing radial force and an angular contact ball bearing axial force are not arranged between the two stages) are proposed. But both of these conventional constructions are subject to axial forces from the high pressure stage to the low pressure stage. Larger axial forces require larger bearings, the size of which is limited by the rotor center-to-center distance.

The prior patent with the publication number of CN112746958B discloses a double-screw compression and expansion integrated machine for a fuel cell, wherein high-pressure orifices are arranged at a position close to the middle of a machine body, and low-pressure orifices are arranged at two ends of the machine body; the female rotor of the compressor is coaxially connected and fixed with the male rotor of the expander, the male rotor of the compressor is also connected with the female rotor of the expander through a rotor shaft, but the male rotor of the compressor is fixed with the rotor shaft, and the female rotor of the expander is in clearance fit with the rotor shaft and slides mutually; the low pressure side of the expander is connected with the motor. In the technical scheme, the balance effect of stress of the compressor rotor and the expander rotor is utilized, so that the load of the bearing is effectively reduced, the power consumption loss of the bearing is reduced, and the problem of low recovery work of the expander in low load is solved. However, this solution, although being able to balance the axial forces, is only applicable to compression-expansion machines.

The utility model patent with the publication number of CN110206729B discloses a self-balancing axial force four-screw mechanical device with a gas thrust bearing, wherein the mechanical device adopts four screws with symmetrically arranged screw threads with opposite screw directions, the screws in the same shell are meshed in pairs, screw threads on the same shaft on different shells are opposite in screw directions, so that the axial forces on two rotors are basically counteracted in the normal operation process of the mechanical device, and the self-balancing of the axial forces is realized; two symmetrical thrust bearings are arranged on each shaft, so that the residual axial force on each shaft can be borne by the two symmetrical thrust bearings and bear the axial force with smaller absolute value and without complete self-balance. The technical scheme adopts the same two pairs of rotors to balance axial force, and is not suitable for coaxial direct drive and single-machine double-stage screw compressors.

Further, the utility model patent of publication number CN205937114U discloses a screw compressor with a symmetrical arrangement of male rotors, comprising: the two male rotors and the two female rotors are coaxially and fixedly connected, the two male rotors are respectively provided with a suction end and a discharge end, and the respective suction ends of the two male rotors are connected with each other or the respective discharge ends of the two male rotors are connected with each other, so that acting forces respectively generated on the two male rotors along the axial direction are mutually offset when the screw compressor is operated; the two female rotors are respectively meshed with the two male rotors. The technical scheme can only balance the axial force of the male rotor and cannot balance the axial force of the female rotor.

From the above, how to simultaneously satisfy the axial force balance requirements of the coaxial direct drive and the single-machine two-stage screw compressor is a technical problem to be solved.

Disclosure of Invention

The utility model provides an axial force balance structure and a double-stage screw compressor applying the same, which are used for solving the problem of axial force balance and simultaneously meeting the use requirements of a coaxial direct-drive and single-machine double-stage screw compressor.

The utility model provides an axial force balancing structure, which comprises an exhaust side bearing seat, a machine body and a rotor, wherein the exhaust side bearing seat is provided with an oil supply hole, and the machine body is provided with an air suction port; the rotor is characterized in that an exhaust side oil hole and an air suction side oil hole are respectively formed in two sides of the axial direction of the rotor, the exhaust side oil hole and the air suction side oil hole are respectively communicated with the oil supply hole and the air suction port, and an internal oil circuit for communicating the exhaust side oil hole and the air suction side oil hole is further formed in the rotor.

In one embodiment, the rotors comprise a male rotor and a female rotor; the exhaust side oil hole includes:

the exhaust side oil hole of the male rotor is arranged on the male rotor and is communicated with the oil supply hole; and

the female rotor exhaust side oil hole is arranged on the female rotor and is communicated with the oil supply hole.

In one embodiment, the oil supply hole includes:

the male side oil supply hole is communicated with the male rotor exhaust side oil hole; and

a female side oil supply hole; is communicated with the exhaust side oil hole of the female rotor.

In one embodiment, the internal oil passage includes:

the inner oil way of the male rotor is arranged in the male rotor and is communicated with the oil hole on the exhaust side of the male rotor; and

and the internal oil way of the female rotor is arranged in the female rotor and is communicated with the exhaust side oil hole of the female rotor.

In one embodiment, the suction side oil hole includes:

the air suction side oil hole of the male rotor is arranged on the male rotor and is communicated with the internal oil way of the male rotor; and

the female rotor air suction side oil hole is arranged on the female rotor and is communicated with an internal oil way of the female rotor.

In one embodiment, the male rotor suction side oil hole and the female rotor suction side oil hole are both in communication with the suction port.

In one embodiment, the rotor is sleeved with a balance piston, and one side of the balance piston, which is close to the machine body, is communicated with the inter-tooth volume of the male rotor and the female rotor of the radial exhaust port.

In one embodiment, the balance piston includes:

the male rotor balance piston is sleeved on the male rotor and is positioned on one side of the male rotor exhaust side bearing close to the engine body; and

the female rotor balance piston is sleeved on the female rotor and is positioned on one side of the female rotor exhaust side bearing close to the machine body.

In one embodiment, the male rotor balance piston and the female rotor balance piston are each provided with a seal portion for sealing a gap between the male rotor balance piston and the exhaust side bearing housing.

In another aspect, the present utility model provides a dual stage screw compressor comprising the axial force balancing structure described above.

In summary, compared with the prior art, the utility model has the following beneficial technical effects: through this axial force balanced structure, reduce the axial force that the rotor receives, not only can widen the high pressure application range of compressor, make it satisfy the coaxial direct drive and the single-machine doublestage screw compressor's of the same time operation demand, can reduce axial bearing quantity moreover, help the compactness of compressor structure, practice thrift the compressor cost, in addition still reduced compressor oil pump consumption, promoted compressor work efficiency.

Drawings

The utility model will be described in more detail hereinafter on the basis of embodiments and with reference to the accompanying drawings. Wherein:

FIG. 1 is an overall schematic of an axial force balancing structure in accordance with one embodiment of the present utility model;

FIG. 2 is a schematic illustration of the structure of a male rotor balance piston in one embodiment of the present utility model;

FIG. 3 is a schematic diagram of a stress analysis of a rotor in an embodiment of the utility model.

Reference numerals: 1. an exhaust side bearing housing; 2. a body; 3. a male rotor; 4. a female rotor; 5. the male rotor exhaust side bearing; 6. female rotor exhaust side bearing; 7. a male rotor suction side bearing; 8. female rotor suction side bearing; 9. a male side oil supply hole; 10. a female side oil supply hole; 11. an exhaust side oil hole of the male rotor; 12. an exhaust side oil hole of the female rotor; 13. an internal oil circuit of the male rotor; 14. an internal oil path of the female rotor; 15. a male rotor balance piston; 16. a female rotor balance piston; 17. a sealing part; 18. the suction side oil hole of the male rotor; 19. the suction side oil hole of the female rotor.

Detailed Description

The present utility model will now be described more fully hereinafter with reference to the accompanying drawings.

Referring to fig. 1, an axial force balancing structure is mainly used for balancing axial force of a rotor in a compressor, and comprises an exhaust side bearing seat 1, a machine body 2 and a rotor arranged between the exhaust side bearing seat 1 and the machine body 2. Wherein, the two ends of the rotor are respectively in running fit with the exhaust side bearing seat 1 and the machine body 2 through bearings.

The exhaust side bearing seat 1 is provided with an oil supply hole, and the machine body 2 is provided with an air suction port (not shown in the figure and can be consistent with the air suction port on a conventional compressor); the two sides of the rotor in the axial direction are respectively provided with an exhaust side oil hole and an air suction side oil hole, the exhaust side oil hole and the air suction side oil hole are respectively communicated with the oil supply hole and the air suction port, and the rotor is internally provided with an internal oil circuit for communicating the exhaust side oil hole and the air suction side oil hole.

In actual operation, lubricating oil is injected from the oil supply hole, one part of the lubricating oil is used for lubricating the exhaust side bearing and flows out through the oil return oil passage, the other part of the lubricating oil enters the exhaust side oil hole, then flows to the suction side bearing through the internal oil passage, then enters the rotor along with the suction air flow to be compressed, and finally is discharged along with the gas from the exhaust side of the compressor. It should be noted that the oil return path inside the compressor belongs to the prior art in the field, and is not the focus of the present utility model, and is not repeated here.

Referring to fig. 1, in the present embodiment, the above-described rotor includes a male rotor 3 and a female rotor 4. The male rotor 3 is in a rotating fit with the exhaust side bearing housing 1 at one end via the male rotor exhaust side bearing 5 and in a rotating fit with the housing 2 at the other end via the female rotor suction side bearing 8 of the female rotor 4. Similarly, the female rotor 4 is provided with a female rotor exhaust bearing 6 and a female rotor suction bearing 8 at both ends thereof for mounting and flexibly rotating the female rotor 4.

The oil supply holes may be provided in two, namely, a male oil supply hole 9 and a female oil supply hole 10. Correspondingly, two exhaust side oil holes are also arranged, and comprise a male rotor exhaust side oil hole 11 arranged on the male rotor 3 and a female rotor exhaust side oil hole 12 arranged on the female rotor 4, wherein the male rotor exhaust side oil hole 11 is communicated with the male side oil supply hole 9, and the female rotor exhaust side oil hole 12 is communicated with the female side oil supply hole 10; thus, a part of the lubricating oil is injected through the male side oil supply hole 9 and enters the male rotor exhaust side oil hole 11; the other part is injected through the female side oil supply hole 10 and enters the female rotor exhaust side oil hole 12.

In another embodiment, only one oil supply hole may be provided so that the lubricating oil is split at the oil supply hole and then flows into the male rotor exhaust side oil hole 11 and the female rotor exhaust side oil hole 12, respectively.

Meanwhile, the internal oil passage includes a male rotor internal oil passage 13 provided inside the male rotor 3 and a female rotor internal oil passage 14 provided inside the female rotor. Correspondingly, the suction-side oil hole includes a male rotor suction-side oil hole 18 provided in the male rotor 3 and a female rotor suction-side oil hole 19 provided in the female rotor 4.

In this embodiment, the internal oil passage 13 of the male rotor may extend along the axial direction of the male rotor 3, and two ends thereof are respectively connected to the exhaust side oil hole 11 of the male rotor and the intake side oil hole 18 of the male rotor; in this way, the lubricating oil, after entering the male rotor exhaust side oil hole 11 through the male side oil supply hole 9, flows along the male rotor internal oil passage 13 to the male rotor intake side oil hole 18. Similarly, the inner-rotor oil passage 14 may extend in the axial direction of the female rotor 4, and both ends thereof may be respectively connected to the exhaust-side oil hole 12 of the female rotor and the intake-side oil hole 19 of the female rotor, so that the lubricating oil, after being injected through the oil supply hole 10 of the female rotor, will flow to the intake-side oil hole 19 of the female rotor through the exhaust-side oil hole 12 of the female rotor and the inner-rotor oil passage 14 of the female rotor.

In another embodiment, the above-mentioned male rotor internal oil passage 13 and female rotor internal oil passage 14 may be provided in the compressor body, and it is only necessary to ensure that the lubricating oil can flow to the male rotor suction side oil hole 18 and the female rotor suction side oil hole 19, that is, only to satisfy that the lubricating oil can flow to the suction port position.

In this embodiment, unlike the conventional compressor, there is no sealing structure at the position of the suction side oil hole 18 of the male rotor and the suction side oil hole 19 of the female rotor, so that the suction side oil hole 18 of the male rotor and the suction side oil hole 19 of the female rotor are both communicated with the suction port on the machine body 2. Thus, the lubricating oil flowing to the male rotor suction side oil hole 18 and the female rotor suction side oil hole 19 will directly leak to the suction port; as the compressor operates and draws in, lubrication oil will enter the rotor interior with the flow of draw air and be compressed, ultimately exiting the compressor discharge side with the flow of draw air.

Referring to fig. 1-2, to further achieve axial force balance, a balance piston is also provided on the rotor. Specifically, the balance pistons include a male rotor balance piston 15 and a female rotor balance piston 16. Wherein, the male rotor balance piston 15 is sleeved on the male rotor 3 and is positioned on one side of the male rotor exhaust side bearing 5 close to the machine body 2, and one side of the male rotor balance piston 15 close to the machine body 2 is communicated with a female and male rotor inter-tooth volume (not shown in the figure) of the radial exhaust port. Similarly, the female rotor balance piston 16 is sleeved on the female rotor 4 and is positioned on the side of the female rotor exhaust side bearing 6 close to the machine body 2, and the side of the female rotor balance piston 16 close to the machine body 2 is also communicated with the inter-tooth volume of the female rotor.

In this embodiment, taking the male rotor balance piston 15 as an example, since the left side of the male rotor balance piston 15 communicates with the chamber in which the male rotor exhaust side bearing 5 is located and the right side thereof communicates with the inter-male rotor space, the pressure applied to the left side of the male rotor balance piston 15 is equal to the oil pressure at the male rotor exhaust side bearing 5, and the pressure applied to the right side thereof is equal to the air pressure in the inter-male rotor space, i.e., the exhaust pressure. Similarly, the left and right sides of the female rotor balance piston 16 are also subjected to oil pressure and exhaust pressure, respectively.

Meanwhile, in order to ensure that the pressures applied to both sides of the male rotor balance piston 15 and the female rotor balance piston 16 are oil pressure and exhaust pressure, respectively, sealing portions 17 are provided on both the male rotor balance piston 15 and the female rotor balance piston 16.

In the present embodiment, the seal portions 17 on the male rotor balance piston 15 and the female rotor balance piston 16 may be of the same structure. Taking the male rotor balance piston 15 as an example, the sealing portion 17 may be a comb tooth sealing structure directly formed on the peripheral side of the male rotor balance piston 15, and the number of comb teeth is at least 3, so as to ensure the sealing effect.

In another embodiment, the sealing portion 17 may be an O-ring separately provided from the male rotor balance piston 15 and the female rotor balance piston 16, that is, an O-ring may be provided at a gap between the male rotor balance piston 15, the female rotor balance piston 16 and the inner wall of the exhaust side bearing housing 1 to achieve sealing.

In this way, the seal 17 can effectively seal the gap between the inner wall of the exhaust-side bearing housing 1 and the male rotor balance piston 15 and the female rotor balance piston 16, and prevent the gas on the right side of the male rotor balance piston 15 and the female rotor balance piston 16 from leaking to the corresponding bearing positions.

In order to verify the balance effect of the axial force born by the rotor in the embodiment, the embodiment carries out stress analysis on the axial force born by the rotor in the working process.

As shown in fig. 3, in the present embodiment, the rotor (including the male rotor 3 and the female rotor 4) receives 6 axial forces in total; f1 is the thrust of the high-pressure gas (exhaust pressure) on the right side of the balance piston (the male rotor balance piston 15 and the female rotor balance piston 16) to the rotor leftward; f2 is the thrust of the low pressure oil on the rotor to the right at the exhaust side bearing (including the male rotor exhaust side bearing 5 and the female rotor exhaust side bearing 6); f3 is the right thrust of the high-pressure gas to the rotor in the exhaust process; f4 is the leftward thrust of the gas in the inter-tooth volume of the male rotor and the female rotor to the male rotor 3, F5 is the rightward thrust of the gas in the inter-tooth volume of the male rotor and the female rotor to the female rotor 4, and the sizes of the F4 and the F5 are similar and the directions are opposite, so that the two can be considered to be mutually offset; f6 is the thrust of the suction gas to the rotor to the left; thus, the axial force to which the rotor is subjected in this model is F2+F3-F1-F6.

Similarly, in a conventional compressor without a balance piston, the axial force of the rotor is f2+f3-F6, i.e., the axial force experienced by the rotor is reduced by F1 in this embodiment compared to a conventional compressor without a balance piston.

Whereas in a conventional compressor provided with a balancing piston, the axial force to which the rotor is subjected is f2+f3-F1-F6. However, even if the balance piston is provided in the conventional compressor, since the lubricating oil on the exhaust side bearing in the conventional oil path structure returns to the compression stage of the male rotor 3 just before the start of compression, that is, the oil pressure is at least greater than the pressure of the male rotor 3 just before the start of compression, which results in greater F2, the axial force balance structure provided in the present embodiment can reduce the axial force applied to the rotor as compared with the conventional compressor provided with the balance piston.

Therefore, by utilizing the axial force balancing structure provided by the embodiment, not only can the oil supply pressure be reduced, but also most of the axial force can be balanced, and the power consumption of the oil pump can be reduced. In addition, because the lubricating oil in the embodiment can enter the inter-tooth volume of the male rotor and the female rotor along with the suction air flow, the low-pressure oil also has a certain cooling effect on the rotor when passing through the interior of the rotor.

The utility model also provides a double-stage screw compressor, which comprises the axial force balancing structure. Specifically, the two-stage screw compressor can be a single-machine two-stage screw compressor or a coaxial direct-drive two-stage screw compressor.

In the description of the present utility model, it should be understood that the terms "upper," "lower," "bottom," "top," "front," "rear," "inner," "outer," "left," "right," and the like indicate orientation or positional relationships based on those shown in the drawings, merely to facilitate describing the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

While the utility model has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the utility model. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present utility model is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims

1. The axial force balancing structure comprises an exhaust side bearing seat, a machine body and a rotor, and is characterized in that an oil supply hole is formed in the exhaust side bearing seat, and an air suction port is formed in the machine body; the rotor is characterized in that an exhaust side oil hole and an air suction side oil hole are respectively formed in two sides of the axial direction of the rotor, the exhaust side oil hole and the air suction side oil hole are respectively communicated with the oil supply hole and the air suction port, and an internal oil circuit for communicating the exhaust side oil hole and the air suction side oil hole is further formed in the rotor.

2. The axial force balancing structure of claim 1, wherein the rotor comprises a male rotor and a female rotor; the exhaust side oil hole includes:

3. The axial force balancing structure of claim 2, wherein the oil supply hole includes:

4. The axial force balancing structure of claim 2 or 3, wherein the internal oil passage includes:

5. The axial force balancing structure according to claim 4, wherein the suction side oil hole includes:

6. The axial force balancing structure according to claim 5, wherein the male rotor suction side oil hole and the female rotor suction side oil hole are both communicated with the suction port.

7. An axial force balance structure according to any one of claims 1-3, wherein the rotor is sleeved with a balance piston, and one side of the balance piston, which is close to the machine body, is communicated with the inter-tooth volume of the male and female rotors of the radial exhaust port.

8. The axial force balancing structure of claim 7, wherein the balancing piston comprises:

9. The axial force balancing structure according to claim 8, wherein the male rotor balance piston and the female rotor balance piston are each provided with a sealing portion for sealing a gap between them and the exhaust side bearing housing.

10. A twin-stage screw compressor comprising an axial force balancing structure according to any one of claims 1-9.