CN113107969A

CN113107969A - Rotor assembly and machining method thereof, compressor and air conditioning equipment

Info

Publication number: CN113107969A
Application number: CN202010021441.5A
Authority: CN
Inventors: 李宏波; 雷连冬; 刘华; 张治平; 陈玉辉
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2020-01-09
Filing date: 2020-01-09
Publication date: 2021-07-13

Abstract

The present invention relates to a rotor assembly and an air conditioning apparatus, wherein the rotor assembly includes: a rotor (2); a first bearing (5) which is a dynamic pressure gas bearing and is used for supporting the rotor (2); and a second bearing (7) for supporting the rotor (2) when the first bearing (5) is in an unstable operating state. In the bearing support structure, the first bearing is a dynamic pressure gas bearing and is used for supporting the rotor when the rotor is in a stable working state with high rotating speed, and at the moment, the friction loss is small, the rotation precision is high, and the stability of the rotor is good; when the rotor is in an unstable working state that the first bearing does not establish a stable air film when the rotor is started, stopped or reversely rotated, the rotor is supported by the second bearing, so that the running stability of the rotor in each working state and the bearing capacity of the bearing can be improved.

Description

Rotor assembly and machining method thereof, compressor and air conditioning equipment

Technical Field

The invention relates to the technical field of air compression equipment, in particular to a rotor assembly and a processing method thereof, a compressor and air conditioning equipment.

Background

The bearing is an essential basic component in the rotating machinery, and the functions of the bearing comprise: the support shaft and its parts on the shaft continue to rotate and reduce friction between the rotor and the support member.

In the current centrifugal compressor, rolling bearings, sliding bearings, magnetic suspension bearings, and the like are commonly used. The rolling bearing has the advantages of small friction resistance, sensitive starting, high efficiency and the like, is widely applied, but has the defects of poor impact resistance and unsuitability for high-rotating-speed environment; the traditional oil sliding bearing has good adaptability in the occasions of high precision, heavy load, belt impact and the like, but is limited by the structure, a lubricating system must be configured and correspondingly sealed, and the complexity of the system is increased; magnetic suspension bearings are widely applied to small and medium-sized compressors in recent years, have the advantages of high rotating speed, no oil, and the like, but have large bearing clearance, and the performance improvement is limited.

With the trend of miniaturization of centrifugal compressors, the industry puts higher and higher demands on bearings, which not only require the bearings to operate at higher rotation speed, but also require extremely high rotation precision. The air bearing has the advantages of small friction loss, almost no friction at extremely high rotating speed, good high-temperature stability, small vibration, no need of lubricating oil and the like, and is gradually applied to a centrifugal compressor.

The air bearings are classified into static pressure gas bearings and dynamic pressure gas bearings according to the difference in the mechanism of generation of a lubricating gas film. The static pressure gas bearing uses an external gas source to supply gas to the bearing to generate pressure bearing load, and the dynamic pressure gas bearing uses a pressure gas film generated by the gas in a wedge-shaped space between a shaft and the inner surface of the bearing to support the load. Compared with static pressure gas bearing, the dynamic pressure gas bearing does not need external gas source, simplifies the structure, and the dynamic pressure effect of the dynamic pressure gas bearing is more obvious along with the increase of the relative movement speed, thus being very suitable for high rotating speed environment.

However, after the dynamic pressure gas bearing is applied to a centrifuge compressor, in the using process, the stability of the rotor operation is found to be poor when the compressor is in the working conditions of starting, stopping or reversing and the like.

Disclosure of Invention

The invention aims to provide a rotor assembly, a processing method thereof, a compressor and air conditioning equipment, which can improve the stability of rotor support.

One aspect of the present invention provides a rotor assembly including:

a rotor;

the first bearing is a dynamic pressure gas bearing and is used for supporting the rotor; and

and the second bearing is used for supporting the rotor when the first bearing is in an unstable working state.

In some embodiments, the rotor assembly further comprises: a second bearing housing for supporting the rotor through the second bearing;

the second bearing comprises a rolling bearing, an inner ring of the rolling bearing is in tight fit with the rotor, and a gap between an outer ring of the rolling bearing and the second bearing seat is smaller than a gap between the first bearing and the rotor.

In some embodiments, the rotor comprises:

the first shaft section is provided with a first bearing;

the second shaft section is provided with a second bearing, and the diameter of the second shaft section is smaller than that of the first shaft section; and

and the guiding part is arranged at the joint of the first shaft section and the second shaft section and used for guiding the refrigerant on the first shaft section to the second shaft section.

In some embodiments, the outer profile of the guide is rounded, sloped or stepped in the longitudinal section of the rotor.

In some embodiments, the rotor assembly includes a support unit provided at least one end of the rotor, the support unit including a first bearing and a second bearing.

In some embodiments, the support unit comprises at least two second bearings arranged at intervals in the axial direction, and each second bearing in the same support unit is arranged on the same side of the first bearing.

In some embodiments, the second bearing in the same support unit is axially outboard of the first bearing.

In some embodiments, the rotor assembly further comprises a housing, the support unit further comprising:

the first bearing seat is connected with the shell and used for supporting the rotor through a first bearing; and

and the second bearing seat is connected to the first bearing seat, is independent from the shell and is used for supporting the rotor through the second bearing.

In some embodiments, one end of the second bearing seat close to the first bearing seat is provided with a first spigot used for limiting the freedom degree of the first bearing seat moving towards the second bearing seat along the axial direction and carrying out thrust on the first bearing; and/or

And a second spigot is arranged on the inner side wall of the shell and used for limiting the freedom degree of the first bearing seat moving away from the second bearing seat along the axial direction.

In some embodiments, the first bearing seat and the second bearing seat are of a split structure or are integrally formed.

In some embodiments, the supporting unit comprises at least two second bearings arranged at intervals along the axial direction, each second bearing in the same supporting unit is arranged on the same side of the first bearing, and the second bearings are rolling bearings;

the supporting unit further includes:

the first spacing piece is arranged between the outer rings of the adjacent second bearings in the supporting unit, and the first spacing piece is in clearance fit with the second bearing seat; and

and the second spacer is arranged between the inner rings of the adjacent second bearings in the supporting unit and is in clearance fit with the rotor.

In some embodiments, the second bearing comprises a rolling bearing, which is an angular contact bearing.

Another aspect of the present invention provides a compressor including the rotor assembly of the above embodiment.

In another aspect, the present invention provides an air conditioning apparatus including the compressor of the above embodiment.

In another aspect, the invention provides a method for processing a rotor assembly based on the above embodiments, including:

the rotor assembly includes: the bearing comprises a shell, a first bearing seat and a second bearing seat, wherein the first bearing seat is provided with a first mounting hole for mounting a first bearing, and the second bearing seat is provided with a second mounting hole for mounting a second bearing; the processing method comprises the following steps:

assembling the first bearing seat, the second bearing seat and the shell into a combined body;

positioning and clamping the combined body on processing equipment;

and machining the first mounting hole and the second mounting hole to a preset size through once positioning and clamping.

In some embodiments, the step of machining the first mounting hole and the second mounting hole to a preset size by one-time positioning and clamping comprises:

and sequentially processing each first mounting hole and each second mounting hole to a preset size from one side of the shell along the axial direction.

In some embodiments, a first spigot is arranged at one end, close to the first bearing seat, of the second bearing seat and used for limiting the freedom degree of the first bearing seat moving towards the direction close to the second bearing seat along the axial direction, and a second spigot is arranged on the inner side wall of the shell and used for limiting the freedom degree of the first bearing seat moving towards the direction far away from the second bearing seat along the axial direction; the step of assembling the first bearing housing, the second bearing housing and the housing as a combination includes:

matching the first bearing seat with the second bearing seat through the first spigot, and matching the first bearing seat with the shell through the second spigot to perform first repositioning;

fixing the first bearing seat and the second bearing seat and the first bearing seat and the shell through fasteners;

after being secured by the fasteners, pins are pinned between the first bearing block and the second bearing block, and between the first bearing block and the housing, for a second repositioning.

In some embodiments, after the processing is completed, the method further comprises:

and disassembling the combined body so as to install the first bearing and the second bearing under the state that the shell, the first bearing seat and the second bearing seat are separated.

Based on the technical scheme, the bearing supporting structure comprises a first bearing and a second bearing, wherein the first bearing is used for supporting the rotor, the first bearing is a dynamic pressure gas bearing and is used for supporting the rotor when the rotor is in a stable working state with high rotating speed, and at the moment, the friction loss is small, the rotating precision is high, and the rotor stability is good; when the rotor is in an unstable working state that the first bearing does not establish a stable air film when the rotor is started, stopped or reversely rotated, the rotor is supported by the second bearing, so that the running stability of the rotor in each working state and the bearing capacity of the bearing can be improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a cross-sectional view of some embodiments of the centrifugal compressor of the present invention;

fig. 2 is a schematic structural view of some embodiments of a first bearing in a centrifugal compressor according to the present invention.

Description of the reference numerals

1. A housing; 2. a rotor; 3. a stator; 4. a first bearing housing; 5. a first bearing; 6. a second bearing housing; 7. a second bearing; 8. a first spacer; 9. a second spacer; 10. a bearing gland; 10', a locking nut;

11. a refrigerant outlet; 12. a guide groove; 13. a refrigerant inlet; 14. a second spigot; 21. a first shaft section; 22. a second shaft section; 23. a third shaft section; 24. a guide section; 31. an aperture; 41. a first mounting hole; 51. a bearing housing; 52. a bump foil; 53. a top foil; 61. a second mounting hole; 611. a first bore section; 612. a second bore section; 62. a first spigot.

Detailed Description

The present invention is described in detail below. In the following paragraphs, different aspects of the embodiments are defined in more detail. Aspects so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature considered to be preferred or advantageous may be combined with one or more other features considered to be preferred or advantageous.

The terms "first", "second", and the like in the present invention are merely for convenience of description to distinguish different constituent elements having the same name, and do not denote a sequential or primary-secondary relationship.

The invention improves the bearing support structure of the centrifugal compressor. For the convenience of describing the improvement point of the present invention, the overall structure of the centrifugal compressor will be explained below.

As shown in fig. 1, taking a two-stage centrifugal compressor as an example, it comprises a compressor casing, a rotor 2 and a stator 3. Rotor 2 and stator 3 form the motor, establish in the compressor housing, and stator 3 is gyration type part, is equipped with the winding on it to be fixed in the compressor housing through the tight fit, in order to make rotor 2 high-speed rotatory through producing magnetic field, stator 3 cover is established outside rotor 2 and is located rotor 2 along axial middle zone,

rotor

2 and 3 clearance fit of stator.

The compressor shell is an irregular cavity part and can be formed by casting, and the compressor shell mainly plays a role in supporting and fixing the stator 3 and the bearing seat. The method comprises the following steps: the first volute and the second volute are respectively arranged at two ends of the shell 1 along the axial direction. The stator 3 is tightly fitted with the housing 1. The casing 1 can be cylindric structure, and rotor 2 establishes the central point at casing 1 and puts, and the both ends of rotor 2 set up an impeller respectively, and the inner of impeller sets up the diffuser, and when the impeller was rotatory at a high speed, gas was along with rotatory, and under the centrifugal force effect, the gas was thrown to the back diffuser and is carried out the diffusion, can turn into the pressure energy with the speed energy of impeller export medium, and the gas after the pressure improvement is discharged from the spiral case.

The working principle of the compressor is as follows: during the working process of the compressor, the rotor 2 rotates at a high speed, gas enters the diffuser through the left impeller, the gas enters the first volute after being compressed at the first stage, the exhaust passage on the first volute guides the compressed gas to the right impeller, the compressed gas enters the right diffuser after the centrifugal action of the right impeller, and the gas enters the second volute after being compressed at the second stage and is exhausted out of the compressor through the exhaust passage on the second volute.

In order to cool the stator 3 during the operation of the compressor, a refrigerant inlet 13 and a refrigerant outlet 11 are formed in the sidewall of the casing 1, and a spiral guide groove 12 is formed in the inner wall of the casing 1 to guide the refrigerant from the motor cavity on the first side of the stator 3 to the motor cavity on the second side, thereby cooling the stator 3 during the flowing process. The gaseous refrigerant formed by cooling the stator 3 returns from the gap between the stator 3 and the rotor 2 to cool the rotor 2. The liquid refrigerant that has not been completely gasified after cooling the stator 3 returns to the motor cavity on the first side through the hole 31 provided in the stator 3 in the axial direction, and is discharged out of the motor cavity through the refrigerant outlet 11.

In order to support the rotor 2, two ends of the rotor 2 are respectively provided with a first bearing 5 for bearing radial force applied when the rotor 2 works, and for the radial bearing, the first bearing 5 adopts a dynamic pressure gas bearing and is supported by a first bearing seat 4, the first bearing seat 4 can be fixed on the shell 1, and the stator 3 is axially positioned between the two first bearings 5.

As shown in fig. 2, the hydrodynamic gas bearing includes, from the outside to the inside: a bearing housing 51, a flexible bump foil 52 and a top foil 53. A dynamic pressure gas film is formed between the top foil 53 and the rotor 2, and when a wedge-shaped structure is formed between the top foil 53 and the rotor 2 rotating at a high speed, the rotor 2 drives gas to move due to gas viscosity, the gas is compressed in the wedge-shaped area, a gas film high pressure is formed, and the rotor 2 is supported to stably operate. When the dynamic pressure gas film is formed, the rotation direction of the rotor 2 is directed from the non-fixed ends of the bump foil 52 and the top foil 53 to the fixed ends so as to satisfy the condition that the gas flows from the large section into the small section, as indicated by the arrow θ.

When the discharge pressure recoils due to an abnormal compressor control program or an abnormal shutdown, there is a possibility that the rotor 2 rotates in the reverse direction, at which time it is difficult to form a stable gas film and the dynamic pressure gas bearing fails. Moreover, during the start-up and shutdown of the compressor, the inner surface of the top foil 53 is in dry frictional contact with the rotor 2 due to the absence of the formation of the film of the hydrodynamic gas bearing, which further increases the wear of the first bearing 5 during frequent start-up and shutdown, and reduces the life. In addition, the dynamic pressure gas bearing realizes oilless, which means that the lubricating oil medium is changed into refrigerant gas with oil, and the gas viscosity is only one thousandth of the oil viscosity, so that the dynamic pressure gas bearing has small support rigidity and low bearing capacity, and when the rotor 2 works at low speed, the gas film bearing capacity is low, so that the bearing capacity is low, and the shafting is unstable.

In order to improve the working stability of the rotor 2 when the first bearing 5 is in the above-mentioned unstable working state, the rotor assembly of the present invention further includes a second bearing 7 for supporting the rotor 2 when the rotor 2 is in the working condition of starting, stopping, reversing or low rotation speed, etc., so that the first bearing 5 is in the unstable working state.

For example, the second bearing 7 may include: at least one of a rolling bearing, a magnetic suspension bearing, and a static pressure gas bearing. The rolling bearing belongs to a contact type bearing, is sensitive in starting, high in bearing capacity, stable in rigidity, simple in arrangement and low in cost, and can enable a shaft system to stably run at a low speed. The magnetic suspension bearing belongs to a non-contact bearing, and the rotor can stably run at low speed by controlling the magnitude of magnetic force. The static pressure gas bearing needs to form a gas film, but the static pressure gas bearing introduces gas from the outside, and can also enable the rotor to stably operate by controlling the pressure of the gas at low speed.

When the rotor 2 is in a high-rotating-speed working condition and the first bearing 5 is in a stable working state, the first bearing 5 supports the rotor 2, and at the moment, the dynamic pressure gas bearing has the advantages of small friction loss, high rotation precision and good rotor stability; when the rotor 2 is in working conditions of starting, stopping, reversing or low rotating speed and the like, and the first bearing 5 is in an unstable working state, the second bearing 7 supports the rotor 2. Therefore, the first bearing 5 and the second bearing 7 can adaptively play a supporting role according to the operation condition of the rotor 2, and the stability of the operation of the rotor 2 in each working state and the bearing capacity of the bearings can be improved. The high rotation speed and the low rotation speed are distinguished by a rotation speed at which the first bearing 5 can establish a stable air film or a rotation speed at which the rotor 2 can be suspended.

In some embodiments, the rotor assembly may further comprise a second bearing seat 6, the second bearing seat 6 being fixedly arranged for supporting the rotor 2 via a second bearing 7. The second bearing 7 comprises a rolling bearing, and an inner ring of the rolling bearing is in close fit with the rotor 2, for example, a transition fit or an interference fit can be adopted; the clearance between the outer ring of the rolling bearing and the second bearing seat 6 is smaller than the clearance between the first bearing 5 and the rotor 2. For example, the gap between the outer ring of the rolling bearing and the second bearing seat 6 is selected to be 10 to 30 μm, and the gap between the first bearing 5 and the rotor 2 is selected to be 30 to 50 μm.

When the first bearing 5 is in an unstable working state, for example, during the starting process of the compressor, a stable air film is not established between the first bearing 5 and the rotor 2, at this time, because the inner ring of the rolling bearing is always connected with the rotor 2, the clearance between the outer ring and the second bearing seat 6 is smaller than the clearance between the first bearing 5 and the rotor 2, and the rolling bearing preferentially supports the rotor 2; when the first bearing 5 is in a stable working state, due to the superiority of the dynamic pressure gas bearing in terms of positioning accuracy, the amplitude of the rotor 2 is small, and the amplitude is smaller than the internal clearance of the rolling bearing, so that the rolling bearing is equivalently in a suspended state, and the first bearing 5 plays a main supporting role for the rotor 2. The supporting mode is simple in structure, adaptive adjustment of the support of the rotor 2 can be achieved only by machining and ensuring the matching relation of the first bearing 5, the rotor 2 and the second bearing seat 6, the operation is reliable, and extra parts are not needed to control the working time of the first bearing 5 and the second bearing 7.

As shown in fig. 1, the rotor 2 includes: a first shaft section 21, a second shaft section 22 and a guide 24. Wherein, be equipped with first bearing 5 on the first shaft section 21, be equipped with second bearing 7 on the second shaft section 22, the diameter of second shaft section 22 is less than first shaft section 21. The guiding portion 24 is disposed at a connection position between the first shaft segment 21 and the second shaft segment 22, and is used for guiding the refrigerant on the first shaft segment 21 to the second shaft segment 22.

When the motor is cooled unevenly, part of liquid refrigerant is not gasified, and is accumulated in the motor cavity on the second side, when the rotor 2 rotates at high speed, the dynamic pressure gas bearing sucks the surrounding refrigerant medium, and the liquid refrigerant is sucked into the gap between the first bearing 5 and the rotor 2 along with the gaseous refrigerant. A proper amount of liquid refrigerant is beneficial to lubricating the bearing and reducing the temperature of the bearing, but when the liquid refrigerant is too much, liquid can accumulate inside the bearing, the space is occupied, the formation of a dynamic pressure air film is influenced, and the vibration amplitude of a shafting is increased.

Through setting up guide portion 24, can make the liquid refrigerant guide to second bearing 7 between first bearing 5 and the rotor 2, not only can prevent that liquid refrigerant from amassing in first bearing 5, do benefit to and establish stable air film, but also can improve the lubricated effect of second bearing 7 (for example antifriction bearing).

For example, as shown in fig. 1, the outer contour of the guide portion 24 is a circular arc in the longitudinal section of the rotor 2, the radius of the circular arc is not R, the circular arc may be concave inward or convex outward, the liquid refrigerant may flow to the second bearing 7 under the guidance of the circular arc surface, and the liquid refrigerant may be accelerated and thrown toward the second bearing 7 by a centrifugal force in conjunction with the high-speed rotation of the rotor 2 during operation. Alternatively, the guide portion 24 may be sloped or stepped.

When at least two second bearings 7 are provided in the axial direction on the second shaft section 22, the liquid refrigerant accumulated in the first bearing 5 can flow to the respective second bearings 7 in sequence. For example, the second bearing 7 is a rolling bearing, and the liquid refrigerant in the first bearing 5 is guided to the inner rolling bearing and then continuously flows to the outer rolling bearing through the play between the balls.

In some embodiments, the rotor assembly comprises a support unit provided at least one end of the rotor 2, the support unit comprising a first bearing 5 and a second bearing 7, i.e. each first bearing 5 is provided with a corresponding second bearing 7.

This structure can make rotor 2 when rotating under the low-speed operating mode, keeps the original mode of support of rotor 2 as far as possible, can improve the stability of rotor when low-speed and high-speed operating mode transition. The structure that all sets up the supporting element to rotor 2 both ends can keep the support mode that rotor 2 both ends were supported all the time, improves the bearing capacity of the stability of rotor 2 work and bearing. Preferably, the supporting units at both ends may be symmetrically disposed to improve the operational stability of the rotor 2.

As shown in fig. 1, the supporting unit includes at least two second bearings 7 arranged at intervals along the axial direction, and each second bearing 7 in the same supporting unit is arranged on the same side of the first bearing 5. This structure simplifies the positioning and supporting structure of the second bearing 7, and also facilitates the assembly and lubrication of the second bearing 7.

As shown in fig. 1, the second bearing 7 in the same support unit is located axially outside the first bearing 5. In this configuration, the first bearing 5 is closer to the motor cooling system, and can be lubricated and cooled by using a suitable amount of liquid refrigerant as a dynamic pressure gas bearing. Further, when the rolling bearing is used as the second bearing 7, wear is likely to occur after long-term use, and the provision of the second bearing outside the first bearing 5 is advantageous for maintenance or replacement of the rolling bearing. Optionally, the second bearing 7 in the same support unit is located axially inside the first bearing 5.

Still referring to fig. 1, the rotor assembly further includes a housing 1, and the supporting unit may further include: a first bearing housing 4 connected to the housing 1 for supporting the rotor 2 through a first bearing 5; and a second bearing housing 6 connected to the first bearing housing 4 and independent from the housing 1 for supporting the rotor 2 through a second bearing 7.

The structure directly connects the second bearing seat 6 to the first bearing seat 4, the original structural form of the shell 1 does not need to be changed, and the volume of the second bearing seat 6 can be reduced. Further, the liquid refrigerant accumulated in the first bearing 5 can enter the second bearing 7 more through the closed cavity formed between the second bearing housing 6 and the rotor 2, and the liquid refrigerant accumulated in the first bearing 5 is prevented from flowing to other regions in the housing 1, thereby improving the lubricating effect of the second bearing 7.

As shown in fig. 1, the second bearing 7 is disposed outside the first bearing 5, one end of the second bearing seat 6 close to the first bearing seat 4 is provided with a first spigot 62, and one end of the first bearing seat 4 is embedded in the first spigot 62 and abuts against a bottom surface of the first spigot 62, so as to limit the degree of freedom of the first bearing seat 4 moving toward the second bearing seat 6 in the axial direction and simultaneously prevent the first bearing 5 from being pushed. The structure can enable the bearing supporting structure to be more compact, and the second bearing seat 6 can limit the first bearing seat 4 while supporting the second bearing 7. Further, the second bearing housing 6 may be fixed to the first bearing housing 4 by fasteners.

Further, a second spigot 14 is provided on the inner side wall of the housing 1 for limiting the freedom of movement of the first bearing seat 4 in the axial direction towards and away from the second bearing seat 6. Thereby, the degrees of freedom of the first bearing housing 4 in both axial directions are restricted.

The first bearing seat 4 and the second bearing seat 6 can adopt a split structure, and are easy to process. Or, the first bearing seat 4 and the second bearing seat 6 are integrally formed, so that the assembly is convenient, and the coaxiality of the corresponding mounting holes of the first bearing 5 and the second bearing 7 is easy to improve.

As shown in fig. 1, the supporting unit includes at least two second bearings 7 arranged at intervals along the axial direction, each second bearing 7 in the same supporting unit is arranged on the same side of the first bearing 5, and the second bearings 7 are rolling bearings. The supporting unit further includes: a first spacer 8 provided between outer rings of adjacent second bearings 7 in the support unit, the first spacer 8 being in clearance fit with the second bearing housing 6, for example in H7/g 6; and a second spacer 9 provided between the inner rings of the adjacent second bearings 7 in the support unit, the second spacer 9 being in a clearance fit with the rotor 2, for example, in H7/g 6.

The first bearing seat 4 is provided with a first mounting hole 41 along the axial direction for mounting the first bearing 5, and the first bearing 5 and the first mounting hole 41 adopt a tight fit, such as a transition fit or an interference fit. When the bearing works, the first bearing 5 utilizes the dynamic pressure gas film to realize precise support on the rotor 2 and parts on the shaft, and the radial runout can be less than 5 mu m. The second bearing seat 6 is provided with a second mounting hole 61 along the axial direction for mounting each second bearing 7 in the same supporting unit, the outer diameter of the second bearing 7 is D2, the inner diameter is D1, when the second bearing 7 is a rolling bearing, the outer ring of the second bearing is in clearance fit with the second mounting hole 61, and the inner ring of the second bearing is in tight fit with the rotor 2. The clearance between the first spacer 8 and the first mounting hole 41 is not smaller than the clearance between the outer race of the second bearing 7 and the second mounting hole 61, and the clearance between the second spacer 9 and the rotor 2 is not smaller than the clearance between the inner race of the second bearing 7 and the rotor 2.

When the support unit comprises at least two second bearings 7, the adjacent second bearings 7 can be arranged at intervals by arranging the spacers, the support effect is optimized, and the mutual influence between the adjacent second bearings 7 is prevented. Due to the positioning function of the first spacer 8 and the second spacer 9, the positioning of the second bearing 7 can be more accurate and the installation is convenient by adopting clearance fit between the first spacer 8 and the second bearing seat 6 and between the second spacer 9 and the rotor 2.

Further, in order to solve the problem of abnormal wear of the bearings when the bearings are frequently started and stopped, the clearance between the second bearing 7 and the second bearing seat 6 is smaller than the clearance between the first bearing 5 and the first bearing seat 4. For example, the second bearing 7 is a rolling bearing, the clearance between the outer ring of the rolling bearing and the second bearing seat 6 is selected within the range of 10-30 μm, and the inner ring of the rolling bearing is in tight fit with the rotor 2, such as transition fit or interference fit; the matching clearance between the first bearing 5 and the rotor 2 is selected within a range of 30-50 μm.

Therefore, the second bearing 7 is preferably operated alone during the start-up or shutdown of the compressor, and the risk of dry friction of the second bearing 7 can be reduced.

As shown in fig. 1, the second bearing seat 6 is a rotary structure, and includes a main body portion and a flange portion connected to the main body portion along an axial direction, and a first spigot 62 is provided on an end surface of the flange portion. The second bearing seat 6 is provided with a second mounting hole 61, the second mounting hole 61 is a stepped hole and includes a first hole section 611 and a second hole section 612, and a stepped surface is formed at a connection position of the first hole section 611 and the second hole section 612. The outer race of the innermost second bearing 7 of the same support unit abuts against the stepped surface and the inner race abuts against the thrust surface formed by the second shaft section 22 and the guide portion 24.

The supporting unit further includes: the rotor 2 further comprises a third shaft section 23, the third shaft section 23 is connected to one end, far away from the first shaft section 21, of the second shaft section 22, the diameter of the third shaft section 23 is smaller than that of the second shaft section 22, the outer ring of the second bearing 7 located on the outermost side in the same supporting unit is limited through the bearing gland 10, and the inner ring of the second bearing is limited through the locking nut 10'. After the bearing gland 10 and the lock nut 10' are installed, the axial clearance s between the bearing gland and the second bearing 7 can be controlled to be 30-50 mu m.

Because the pressure of the air outlet is greater than the pressure of the air inlet when the impeller of the compressor does work on the refrigerant in the working process, the pressure difference can generate axial force and radial force, and in order to balance the axial force applied to the rotor 2, the second bearing 7 can adopt an angular contact rolling bearing. Therefore, a thrust disc and a gas thrust bearing can be omitted from the compressor, the structure can be simplified, the working reliability of the bearing is improved, and the cost is reduced.

When the exhaust pressure is backflushed due to abnormal program or abnormal shutdown, the rotor 2 can rotate reversely, the first bearing 5 cannot form an air film and fails, the second bearing 7 works, and the angular contact type rolling bearing can simultaneously bear the axial force and the radial force applied to the rotor 2.

The angular contact rolling bearing can adopt at least one of the following arrangement modes:

first, both ends of rotor 2 respectively are equipped with a supporting element, all include a first bearing 5 and a second bearing 7 in every supporting element, and second bearing 7 in the supporting element of both ends is the reverse installation. Since the axial force is related to the structure and the rotating speed of the rotor 2 and the working condition of the compressor, the direction of the axial force is uncertain, and the structure can balance the axial force applied to the rotor 2 in two directions simultaneously.

And secondly, two ends of the rotor 2 are respectively provided with a supporting unit, each supporting unit comprises a first bearing 5 and at least two second bearings 7, each second bearing 7 in the same supporting unit is installed in the same direction, and the second bearings 7 in the supporting units at the two ends are installed in opposite directions. The structure can balance the axial force of the rotor 2 in two directions and improve the bearing capacity by increasing the number of the second bearings 7.

And thirdly, two ends of the rotor 2 are respectively provided with a supporting unit, each supporting unit comprises a first bearing 5 and two second bearings 7, and the two second bearings 7 in the same supporting unit are reversely installed. The structure can balance the axial force of the rotor 2 in two directions through one supporting unit, can prevent the axial force received by one end of the rotor 2 from being transmitted to the other end, and can prolong the service life of each component in the shafting.

The rotor assembly of the invention adopts a multi-bearing self-adaptive adjustment mode, and can realize high-precision operation of the centrifugal compressor at low-speed and high-speed stages. The characteristics of sensitive starting, high bearing capacity and stable rigidity of the rolling bearing are utilized, and the rolling bearing is tightly matched with the rotor 2, so that the rotor 2 can be automatically supported by the rolling bearing at a low rotating speed, and the rotating precision of the rotor 2 is 10-30 mu m. Simultaneously, four angle contact bearings are unilateral in pairs use, both sides symmetrical arrangement, can improve bearing capacity on the one hand like this, and on the other hand also effectively balances the axial force that shafting and bearing self produced. When the rotating speed of the compressor is increased, the dynamic pressure effect is more obvious along with the increase of the speed, a dynamic pressure gas film is gradually formed, the dynamic pressure gas bearing gradually plays a supporting role, after the dynamic pressure gas film is completely formed, the vibration amplitude of the rotor is smaller than 5 micrometers due to the high stability of the gas film, the dynamic pressure gas bearing works independently, the rolling bearing does not work, and the high-precision operation at a high rotating speed is realized.

Secondly, the invention also provides a compressor, such as a centrifugal compressor or a screw compressor, and the like, comprising the rotor assembly of the embodiment. The rotor assembly of the invention can improve the running stability of the rotor in each working state and the bearing capacity of the bearing, thereby optimizing the working performance of the centrifugal compressor and prolonging the service life, and moreover, the rotor can stably rotate and reduce the noise generated in the working process of the compressor.

The invention further provides air conditioning equipment comprising the compressor of the embodiment. The air conditioning equipment has higher working stability and reliability.

In addition, the invention also provides a processing method of the rotor assembly based on the above embodiments, and in some embodiments, the rotor assembly includes: the bearing comprises a shell 1, a first bearing seat 4 and a second bearing seat 6, wherein a first mounting hole 41 for mounting a first bearing 5 is formed in the first bearing seat 4, and a second mounting hole 61 for mounting a second bearing 7 is formed in the second bearing seat 6; the processing method comprises the following steps:

step 101, assembling a first bearing seat 4, a second bearing seat 6 and a shell 1 into a combined body;

102, positioning and clamping the assembly on processing equipment;

and 103, machining the first mounting hole 41 and the second mounting hole 61 to a preset size through one-time positioning and clamping.

Wherein, steps 101 to 103 are executed in sequence. This embodiment is through processing under the state at first bearing frame 4, second bearing frame 6 and casing 1 location and formation assembly, and the installation accuracy of bearing is guaranteed to the machining accuracy of accessible assembly, through once the location clamping moreover, can adopt unified processing benchmark to guarantee the axiality of each first mounting hole 41 and second mounting hole 61, improve positioning accuracy, make rotor 2 work more stable.

In some embodiments, the step 103 of machining the first mounting hole 41 and the second mounting hole 61 to the preset size by one-time positioning and clamping includes:

step 103', the respective first mounting holes 41 and the respective second mounting holes 61 are sequentially machined to a preset size from one side of the housing 1 in the axial direction.

Each first mounting hole 41 and each second mounting hole 61 can be processed by adopting a boring mode, and the processing cutter is sequentially processed from one side of the shell 1 by axial feeding, so that the processing efficiency can be improved, the coaxiality of each first mounting hole 41 and each second mounting hole 61 can be further improved, the positioning precision is improved, and the rotor 2 can work more stably.

In some embodiments, a first stop 62 is disposed at an end of the second bearing seat 6 close to the first bearing seat 4 for limiting the freedom of the first bearing seat 4 to move axially toward the direction close to the second bearing seat 6, and a second stop 14 is disposed on an inner side wall of the housing 1 for limiting the freedom of the first bearing seat 4 to move axially toward the direction away from the second bearing seat 6.

On this basis, the step 101 of assembling the first bearing seat 4, the second bearing seat 6 and the housing 1 into a combined body includes:

step 101A, matching the first bearing seat 4 and the second bearing seat 6 through the first spigot 62, and matching the first bearing seat 4 and the housing 1 through the second spigot 14 to perform a first repositioning, wherein the sequence of the two matching assembly links is not limited;

step 101B, fixing the first bearing seat 4 and the second bearing seat 6, and the first bearing seat 4 and the shell 1 through fasteners;

step 101C, after being fixed by the fasteners, pins are pinned between the first bearing housing 4 and the second bearing housing 6, and between the first bearing housing 4 and the housing 1, for a second repositioning.

In this embodiment, steps 101-103 are performed sequentially.

After the first spigot 62 and the second spigot 14 are initially positioned, the position relation of the first bearing seat 4, the second bearing seat 6 and the shell 1 is restrained through the fasteners, on the basis of the original pin holes, the pin holes are formed between the first bearing seat 4 and the second bearing seat 6 and between the first bearing seat 4 and the shell 1 in a matched mode, pins are inserted into the pin holes, the pins can be used for preventing position change of all parts caused by large cutting force in the machining process, and accurate positioning can also be provided for the subsequent product assembling process. By adopting double positioning, the mounting accuracy between the first bearing seat 4, the second bearing seat 6 and the housing 1 can be accurately ensured, thereby improving the coaxiality of the first bearing 5 and the second bearing 7.

In some embodiments, after machining, such machining methods may further comprise:

and 104, disassembling the combined body so as to install the first bearing 5 and the second bearing 7 in a state that the shell 1, the first bearing seat 4 and the second bearing seat 6 are separated.

In the assembling process, the assembling precision of the first bearing 5 and the second bearing 7 can be ensured by the spigot and pin dual positioning mode, and the stability of the bearing rotor system is improved.

The details of the rotor assembly, the processing method thereof, the compressor and the air conditioning equipment provided by the invention are described above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to aid in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. A rotor assembly, comprising:

a rotor (2);

a first bearing (5) which is a dynamic pressure gas bearing and is used for supporting the rotor (2); and

a second bearing (7) for supporting the rotor (2) when the first bearing (5) is in an unstable operating state.

2. The rotor assembly of claim 1, further comprising: a second bearing housing (6) for supporting the rotor (2) by means of the second bearing (7);

the second bearing (7) comprises a rolling bearing, an inner ring of the rolling bearing is in tight fit with the rotor (2), and a gap between an outer ring of the rolling bearing and the second bearing seat (6) is smaller than a gap between the first bearing (5) and the rotor (2).

3. The rotor assembly according to claim 1, wherein the rotor (2) comprises:

the first shaft section (21), the first bearing (5) is arranged on the first shaft section (21);

the second shaft section (22) is provided with the second bearing (7), and the diameter of the second shaft section (22) is smaller than that of the first shaft section (21); and

and a guide portion (24) which is arranged at the joint of the first shaft section (21) and the second shaft section (22) and is used for guiding the refrigerant on the first shaft section (21) to the second shaft section (22).

4. The rotor assembly according to claim 3, characterized in that the outer contour of the guide (24) is rounded, sloped or stepped in the longitudinal section of the rotor (2).

5. The rotor assembly according to claim 1, characterized by comprising a support unit provided at least one end of the rotor (2), the support unit comprising the first bearing (5) and the second bearing (7).

6. The rotor assembly according to claim 5, wherein the support unit comprises at least two second bearings (7) arranged at intervals in the axial direction, each second bearing (7) in the same support unit being arranged on the same side of the first bearing (5).

7. The rotor assembly according to claim 5, characterized in that the second bearing (7) in the same support unit is located axially outside the first bearing (5).

8. The rotor assembly according to claim 5, further comprising a housing (1), the support unit further comprising:

a first bearing housing (4) connected to the housing (1) for supporting the rotor (2) by means of the first bearing (5); and

a second bearing block (6) connected to the first bearing block (4) and independent from the housing (1) for supporting the rotor (2) through the second bearing (7).

9. The rotor assembly of claim 8,

one end, close to the first bearing seat (4), of the second bearing seat (6) is provided with a first spigot (62) used for limiting the freedom degree of the first bearing seat (4) moving towards the second bearing seat (6) along the axial direction and carrying out thrust on the first bearing (5); and/or

And a second spigot (14) is arranged on the inner side wall of the shell (1) and used for limiting the degree of freedom of the first bearing seat (4) moving towards the direction far away from the second bearing seat (6) along the axial direction.

10. The rotor assembly according to claim 8, wherein the first bearing seat (4) and the second bearing seat (6) are of a split structure or are integrally formed.

11. The rotor assembly according to claim 8, wherein the supporting unit comprises at least two second bearings (7) arranged at intervals along the axial direction, each second bearing (7) in the same supporting unit is arranged on the same side of the first bearing (5), and the second bearings (7) are rolling bearings;

the supporting unit further includes:

the first spacing piece (8) is arranged between the outer rings of the adjacent second bearings (7) in the supporting unit, and the first spacing piece (8) is in clearance fit with the second bearing seat (6); and

and the second spacer (9) is arranged between the inner rings of the adjacent second bearings (7) in the supporting unit, and the second spacer (9) is in clearance fit with the rotor (2).

12. The rotor assembly according to claim 1, characterized in that the second bearing (7) comprises an angular contact rolling bearing.

13. A compressor comprising a rotor assembly as claimed in any one of claims 1 to 12.

14. An air conditioning apparatus, characterized by comprising the compressor of claim 13.

15. A method for processing a rotor assembly according to any one of claims 1 to 12, wherein the rotor assembly comprises: the bearing comprises a shell (1), a first bearing seat (4) and a second bearing seat (6), wherein a first mounting hole (41) for mounting a first bearing (5) is formed in the first bearing seat (4), and a second mounting hole (61) for mounting a second bearing (7) is formed in the second bearing seat (6); the processing method comprises the following steps:

assembling the first bearing block (4), the second bearing block (6) and the housing (1) as a combination;

positioning and clamping the combined body on processing equipment;

and machining the first mounting hole (41) and the second mounting hole (61) to preset sizes through one-time positioning and clamping.

16. The machining method according to claim 15, wherein the step of machining the first mounting hole (41) and the second mounting hole (61) to a preset size by one-time positioning and clamping comprises:

and machining each first mounting hole (41) and each second mounting hole (61) to a preset size in sequence from one side of the shell (1) in the axial direction.

17. The machining method according to claim 15, characterized in that a first spigot (62) is provided at one end of the second bearing seat (6) close to the first bearing seat (4) for limiting the freedom of movement of the first bearing seat (4) in the axial direction towards the direction close to the second bearing seat (6), and a second spigot (14) is provided at the inner side wall of the housing (1) for limiting the freedom of movement of the first bearing seat (4) in the axial direction away from the second bearing seat (6); the step of assembling the first bearing block (4), the second bearing block (6) and the housing (1) as a combination comprises:

-engaging the first bearing seat (4) with the second bearing seat (6) through the first spigot (62) and engaging the first bearing seat (4) with the housing (1) through the second spigot (14) for a first repositioning;

fixing the first bearing seat (4) and the second bearing seat (6) and the first bearing seat (4) and the shell (1) by fasteners;

after being fixed by the fasteners, pins are pinned between the first bearing block (4) and the second bearing block (6), and between the first bearing block (4) and the housing (1), for a second repositioning.

18. The method of processing of claim 15, further comprising, after processing is complete:

disassembling the assembly to mount the first bearing (5) and the second bearing (7) in a state where the housing (1), the first bearing housing (4), and the second bearing housing (6) are separated.