Two-stage impeller structure for refrigeration centrifugal compressor

Abstract

The utility model relates to a two-stage impeller structure for a refrigeration centrifugal compressor. The two-stage impeller structure comprises a first-stage impeller, a second-stage impeller, a balance disc and a motor spindle which are sequentially arranged from front to back. The first-stage impeller and the second-stage impeller are in key transmission, the second-stage impeller and the balance disc are in key transmission, the balance disc and the motor main shaft are in key transmission, the front end of the motor main shaft is connected with an impeller locking screw penetrating through the centers of the first-stage impeller and the second-stage impeller, and the front end of the impeller locking screw is connected with an impeller locking nut. Reliable installation of the two-stage impeller is facilitated; the length of the motor main shaft can be effectively shortened, the structure of the motor main shaft is simplified, too large reducing caused by the fact that the motor main shaft needs to penetrate through the impeller is avoided, and the strength of the motor main shaft is improved. The second-stage impeller is driven through a key and is more stable and reliable compared with pin transmission, transmission does not need to be enhanced through interference fit, and the disassembly and assembly difficulty of the second-stage impeller can be reduced; due to the split design of the second-stage impeller and the balance disc, the length of the second-stage impeller is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of refrigeration centrifugal compressor, especially a two-stage impeller structure for refrigeration centrifugal compressor. BACKGROUND

[0002] In the refrigeration compressor application, compared with the screw machine, the centrifugal machine has the advantages of large refrigerating capacity, stability and reliability, low noise, simple maintenance and the like, and is widely used in the market. The refrigeration centrifugal machine obtains kinetic energy through the rotation of the impeller, and then converts the kinetic energy into pressure energy in the expansion chamber, thereby realizing the effect of pressure increase. Therefore, the impeller is the most important part in the refrigeration centrifugal compressor and is the only component that does work in the compressor. There are usually two ways to achieve a larger compression ratio for the compressor: one is to increase the speed of the motor to drive the impeller to a higher speed to obtain more kinetic energy; the other is to set multiple impellers to form multi-stage compression, so that the refrigerant obtains energy multiple times and finally obtains higher pressure. Since the centrifugal machine usually has a high speed, when multi-stage compression is performed, the cantilever of the impeller is longer, and therefore a reliable impeller mounting method is needed.

[0003] The usual scheme is that the motor main shaft is in interference fit with the impeller, each impeller is sequentially installed after being heated and expanded, and is driven by a pin, and finally a nut is used to fasten the front end of the first-stage impeller. This scheme has the following problems: the motor main shaft needs to pass through two impellers, and therefore the size needs to be greatly lengthened; the inner hole diameter of the impeller is usually small, and if the motor main shaft needs to pass through the impeller, the diameter needs to be greatly changed, which affects the strength of the main shaft; the second-stage impeller needs to be in interference fit with the motor main shaft to ensure coaxiality, which makes it difficult to disassemble and assemble the second-stage impeller and increases the difficulty of later maintenance; during the operation of the compressor, the transmission pin is subjected to long-term stress, which is prone to deformation and eventually breaks and causes transmission failure, thereby affecting the long-term stable operation of the compressor; to ensure the balance of the axial force of the rotating part, the diameter of the rear disc of the second-stage impeller is usually large, which increases the volume of the impeller. SUMMARY

[0004] Therefore, the utility model aims to provide a two-stage impeller structure for refrigeration centrifugal compressor, which is convenient to disassemble and assemble and stable and reliable, simplifies the structure of the motor main shaft, and reduces the forming difficulty of the second-stage impeller.

[0005] The utility model adopts the following scheme: a two-stage impeller structure for refrigeration centrifugal compressor, comprising a first-stage impeller, a second-stage impeller, a balance disc and a motor main shaft which are sequentially arranged from front to back; the first-stage impeller and the second-stage impeller are driven by a key, the second-stage impeller and the balance disc are driven by a key, the balance disc and the motor main shaft are driven by a key, and the front end of the motor main shaft is connected with an impeller locking screw rod which passes through the center of the first-stage impeller and the second-stage impeller, and the front end of the impeller locking screw rod is connected with an impeller locking nut.

[0006] Further, the motor main shaft is in the shape of a stepped shaft, the front end of the motor main shaft is a small-diameter section, the rear end is a large-diameter section, the balance disc is sleeved on the small-diameter section of the motor main shaft, and the rear end center portion of the hub of the secondary impeller is provided with a secondary matching hole in clearance fit with the small-diameter section of the motor main shaft.

[0007] Further, the outer side portion of the small-diameter section of the motor main shaft and the inner side portion of the balance disc are provided with balance disc transmission grooves in position correspondence, and the balance disc transmission grooves are provided with balance disc transmission keys.

[0008] Further, the front end center portion of the hub of the secondary impeller is provided with a circular boss, and the rear end center portion of the hub of the primary impeller is provided with a primary matching hole in interference fit with the circular boss.

[0009] Further, the front end side portion of the hub of the secondary impeller is provided with a primary impeller transmission groove, and the rear end side portion of the hub of the primary impeller is provided with a primary impeller transmission key which extends rearward and matches the primary impeller transmission groove.

[0010] Further, the rear end side portion of the hub of the secondary impeller is provided with a secondary impeller transmission groove, and the front end side portion of the balance disc is provided with a secondary impeller transmission key which extends forward and matches the secondary impeller transmission groove.

[0011] Further, the front end and the rear end of the impeller locking screw are respectively provided with external thread portions, the rear end of the impeller locking screw is connected with the front end of the motor main shaft through threads, and the front end center portion of the primary impeller is provided with a locking nut matching groove which is in close fit with the outer diameter of the impeller locking nut.

[0012] Compared with the prior art, the double-stage impeller structure for the refrigeration centrifugal compressor has the following beneficial effects: the double-stage impeller structure for the refrigeration centrifugal compressor is reasonable in design and is favorable for reliable installation of the double-stage impeller; the length of the motor main shaft can be effectively shortened, the structure of the motor main shaft is simplified, the diameter change of the motor main shaft caused by the motor main shaft needing to pass through the impeller is avoided, the machining difficulty of the motor main shaft is reduced, the strength of the motor main shaft is improved, the secondary impeller is driven through keys, the driving is more stable and reliable compared with driving through pins, the driving does not need to be strengthened through interference fit, the dismounting and mounting difficulty of the secondary impeller is reduced, the double-stage impeller and the balance disc are designed in a split mode, the length of the secondary impeller is reduced, the diameter of the rear disc of the secondary impeller is reduced, and the total mass is reduced.

[0013] In order to make the purpose, the technical scheme and the advantages of the utility model more clearly and clearly, the following will be through the specific embodiment and the relevant drawings, to the utility model make further detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the side view of the double-stage impeller structure of the utility model embodiment;

[0015] Figure 2The utility model embodiment two stage impeller structure section view;

[0016] Mark explanation in drawing: 1 - primary impeller, 2 - secondary impeller, 3 - balance disc, 4 - motor main shaft, 5 - balance disc transmission key, 6 - balance disc transmission groove, 7 - impeller locking screw, 8 - impeller locking nut, 9 - locking nut matching groove, 10 - primary impeller transmission key, 11 - primary impeller transmission groove, 12 - secondary impeller transmission key, 13 - secondary impeller transmission groove. DETAILED DESCRIPTION

[0017] It should be noted that the following detailed description is exemplary and is intended to provide further description of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments consistent with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, devices, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, steps, operations, devices, components and / or combinations thereof.

[0019] As Figure 1 , 2The utility model discloses a kind of two-stage impeller structures for refrigeration centrifugal compressor, including sequentially arranged from front to back first-stage impeller 1, second-stage impeller 2, balance disc 3 and motor main shaft 4;First-stage impeller 1 and second-stage impeller 2 are driven by key, second-stage impeller 2 and balance disc 3 are driven by key, balance disc 3 and motor main shaft 4 are driven by key, motor main shaft 4 front end is connected with the impeller locking screw rod 7 that passes through the center of first-stage impeller 1 and second-stage impeller 2, impeller locking screw rod 7 front end is connected with impeller locking nut 8.All transmission of the utility model two-stage impeller structure is realized by key, it is more stable and reliable compared with pin transmission, avoids transmission failure due to pin deformation or fracture;Increase impeller locking screw rod, can effectively shorten the length of motor main shaft, reduce motor main shaft extension length also can make motor become more independent component;It can simplify the structure of motor main shaft, avoid because motor main shaft needs to pass to first-stage impeller front end and make diameter greatly change, reduce the machining difficulty of motor main shaft, also improve the strength of motor main shaft itself, also avoid motor assembly after assembly is completed, shaft extension is too long, influence motor storage and transportation;Second-stage impeller and balance disc split design, balance the axial force of rotating member through the outer diameter of balance disc 3, reduce the length of second-stage impeller, also reduce the forming difficulty of second-stage impeller, while guaranteeing the premise of rear disc diameter, also effectively reduce the volume of transmission member, i.e.

[0020] In the embodiment, the motor main shaft 4 is in the shape of a stepped shaft, the front end of the motor main shaft 4 is a small-diameter section, the rear end is a large-diameter section, the balance disc 3 is sleeved on the small-diameter section of the motor main shaft 4, and the center part of the rear end of the hub of the second-stage impeller 2 is provided with a second-stage matching hole in clearance fit with the small-diameter section of the motor main shaft 4.

[0021] In the embodiment, the small-diameter section of the motor main shaft 4 and the inner side of the balance disc 3 are provided with a balance disc transmission groove 6 in position correspondence, and the balance disc transmission groove 6 is provided with a balance disc transmission key 5.

[0022] In the embodiment, the center part of the front end of the hub of the second-stage impeller 2 is provided with a circular boss, and the center part of the rear end of the hub of the first-stage impeller 1 is provided with a first-stage matching hole in interference fit with the circular boss.

[0023] In the embodiment, the hub front end side of the secondary impeller 2 is provided with a primary impeller transmission groove 11, and the hub rear end side of the primary impeller 1 is provided with a primary impeller transmission key 10 extending rearward and matched with the primary impeller transmission groove 11.

[0024] In the embodiment, the hub rear end side of the secondary impeller 2 is provided with a secondary impeller transmission groove 13, and the front end side of the balance disc 3 is provided with a secondary impeller transmission key 12 extending forward and matched with the secondary impeller transmission groove 13.

[0025] In the embodiment, the front and rear ends of the impeller locking screw 7 are respectively provided with external thread parts, and the rear end of the impeller locking screw 7 is connected with the front end of the motor main shaft 4 through thread connection; the front end center part of the primary impeller 1 is provided with a locking nut matched groove 9 matched with the outer diameter of the impeller locking nut 8, and the impeller locking nut is locked to press the primary impeller 1, the secondary impeller 2, the balance disc 3 and the motor main shaft 4, so that the rotation is more reliable, and the overall coaxiality is better ensured through the impeller locking nut and the locking nut matched groove.

[0026] All the transmission is realized through keys, which is more stable and reliable than pin transmission, and avoids transmission failure caused by pin deformation or fracture; the secondary impeller and the motor main shaft are transmitted through the key transmission, so that the interference fit is not needed, and the impeller is convenient to disassemble and maintain; the primary impeller and the secondary impeller are transmitted through the interference fit to ensure the coaxiality, and are transmitted through the cooperation of the transmission key and the transmission groove; the secondary impeller and the balance disc are designed in a split manner, which reduces the length of the secondary impeller, reduces the forming difficulty of the secondary impeller, effectively reduces the volume of the transmission part under the premise of ensuring the diameter of the rear disc, and reduces the weight of the transmission part; the secondary impeller and the balance disc are also transmitted through the cooperation of the transmission key and the transmission groove, and the coaxiality is ensured through the clearance fit; the balance disc and the motor main shaft are also transmitted through the cooperation of the transmission key and the transmission groove, and the coaxiality is ensured through the clearance fit; the impeller locking screw is added, which can avoid that the motor main shaft is greatly changed in diameter and lengthened to the front end of the primary impeller, reduces the machining difficulty of the motor main shaft, improves the strength of the motor main shaft itself, avoids that the shaft is too long after the motor assembly is completed, and affects the storage and transportation of the motor; the impeller is axially tensioned through the impeller locking nut, and the coaxiality is improved through the impeller locking nut and the locking nut matched groove.

[0027] Any of the above-mentioned technical solutions of the utility model discloses, if it discloses numerical range except declaration, then the numerical range disclosed is preferred numerical range, and any person skilled in the art should understand that: preferred numerical range is only the numerical value of obvious technical effect or representative numerical value among many implementable numerical values. Because there are many values, it is impossible to enumerate, therefore, the utility model discloses only part of values to illustrate the technical scheme of the utility model, and the above-mentioned enumerated values should not constitute the limitation of the protection scope of the utility model.

[0028] If the utility model discloses or involves mutually fixed connecting parts or structural members, then, except declaration, fixed connection can be understood as: detachably fixed connection (for example, bolt or screw connection), and can also be understood as: undetachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by integral structure (for example, integrally formed by using casting process) (except obviously cannot adopt integral forming process).

[0029] In addition, the terms used for indicating position relationship or shape in any of the above-mentioned technical solutions of the utility model disclose, except declaration, its meaning includes approximate, similar or close state or shape.

[0030] Any component provided by the utility model can be assembled by multiple individual components, or can be an individual component manufactured by integral forming process.

[0031] The above-mentioned is only the preferred embodiment of the utility model, and is not other forms of the limitation of the utility model, and any person skilled in the art can change or modify the equivalent embodiment of equivalent change by using the disclosed technical content. However, any simple modification, equivalent change and modification of the above-mentioned embodiment, which does not deviate from the technical scheme content of the utility model, according to the technical essence of the utility model, still belongs to the protection scope of the technical scheme of the utility model.

Claims

1. A two-stage impeller structure for a refrigeration centrifugal compressor, characterized by: The motor main shaft is in the shape of a stepped shaft, the front end of the motor main shaft is a small-diameter section, the rear end is a large-diameter section, the balance disc is sleeved on the small-diameter section of the motor main shaft, and the rear end center of the hub of the secondary impeller is provided with a secondary matching hole in clearance fit with the small-diameter section of the motor main shaft.

2. A two-stage impeller structure for a refrigeration centrifugal compressor according to claim 1, characterized in that: The small-diameter section of the motor main shaft and the inner side of the balance disc are provided with balance disc transmission grooves in position correspondence, and the balance disc transmission grooves are provided with balance disc transmission keys.

3. A two-stage impeller structure for a refrigeration centrifugal compressor according to claim 2, characterized in that: The front end center of the hub of the secondary impeller is provided with a circular boss, and the rear end center of the hub of the primary impeller is provided with a primary matching hole in interference fit with the circular boss.

4. A two-stage impeller structure for a refrigeration centrifugal compressor according to claim 1, characterized in that: The front end side of the hub of the secondary impeller is provided with a primary impeller transmission groove, and the rear end side of the hub of the primary impeller is provided with a primary impeller transmission key which extends rearward and matches the primary impeller transmission groove.

5. A two-stage impeller structure for a refrigeration centrifugal compressor according to claim 4, characterized in that: The rear end side of the hub of the secondary impeller is provided with a secondary impeller transmission groove, and the front end side of the balance disc is provided with a secondary impeller transmission key which extends forward and matches the secondary impeller transmission groove.

6. A two-stage impeller structure for a refrigeration centrifugal compressor according to claim 1, characterized in that: The front end and the rear end of the impeller locking screw rod are respectively provided with external thread parts, the rear end of the impeller locking screw rod is connected with the front end of the motor main shaft through threads, and the front end center of the primary impeller is provided with a locking nut matching groove which is in close fit with the outer diameter of the impeller locking nut.

7. A two-stage impeller structure for a refrigeration centrifugal compressor according to claim 1, characterized in that: ​

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