WO2022111294A1

WO2022111294A1 - Gas bearing and centrifugal compressor having same

Info

Publication number: WO2022111294A1
Application number: PCT/CN2021/130110
Authority: WO
Inventors: 尹泳; 俞国新; 朱万朋; 韩聪; 常云雪; 殷纪强; 李思茹
Original assignee: 青岛海尔智能技术研发有限公司; 海尔智家股份有限公司
Priority date: 2020-11-24
Filing date: 2021-11-11
Publication date: 2022-06-02
Also published as: CN214274252U

Abstract

A gas bearing and a centrifugal compressor (1) having same. The gas bearing comprises a bearing base body (110), a top foil (130) and a bump foil (120) arranged between the bearing base body (110) and the top foil (130), wherein the bump foil (120) comprises a plurality of bumps (122) arranged at intervals, each bump (122) is provided with a fitting face (122a) facing the top foil (130), and the fitting face (122a) is attached to the surface of the top foil (130) in a face contact manner.

Description

Gas bearing and centrifugal compressor having the same

technical field

The present invention relates to the technical field of compressors, in particular to a gas bearing and a centrifugal compressor having the same.

Background technique

With the continuous development of centrifugal compression technology, the requirements for bearings of centrifugal compressors are also increasing. At present, in the prior art, a gas bearing using the compressor working medium as a lubricant has appeared, and it has attracted people's attention due to its features of high efficiency and small energy loss.

However, the gas bearing in the prior art also has certain defects in practical use. For example, in the gas bearing of the prior art, an aluminum foil is generally arranged between the bearing bush and the casing to play a supporting role. However, because the supporting surface is too small, the overall strength of the gas bearing may be unqualified, resulting in abnormal operation in actual operation. Vibration reduces the service life of the gas bearing, making it difficult to adapt to high-speed operating conditions.

SUMMARY OF THE INVENTION

An object of the present invention is to overcome at least one defect in the prior art and provide a gas bearing with improved support force and stability.

A further object of the present invention is to improve the stiffness and pressure resistance of the top foil when the gas bearing is used as a radial or circumferential bearing.

In particular, the present invention provides a gas bearing comprising:

A bearing base, a top foil, and a corrugated foil disposed between the bearing base and the top foil; wherein,

The corrugated foil includes a plurality of arched portions arranged at intervals, and each of the arched portions has an adhering surface facing the top foil, and the adhering surface is adhered to the surface of the top foil in a surface-contact manner.

Further, the gas bearing is a radial bearing, and the corrugated foil is cylindrical as a whole; and

The abutting surface of each arch portion is a circular arc surface matching the shape of the outer circular surface of the top foil.

Further, the corrugated foil extends in a trapezoidal wave shape in the circumferential direction of the gas bearing, and the trapezoidal top surface of the corrugated foil facing the top foil constitutes a bonding surface.

Further, the top foil to bearing base diameter ratio is between 0.8 and 1.2.

Further, the gas bearing is an axial bearing, and the top foil is in the shape of a flat plate as a whole; and

The abutting surface of each arch is a flat surface.

Further, the bearing base is in the shape of an annular flat plate;

The corrugated foil extends in a trapezoidal wave shape in the radial direction of the bearing base, and the trapezoidal top surface of the corrugated foil facing the top foil constitutes a bonding surface.

Further, the number of the top foils is multiple and uniformly arranged along the circumferential interval of the bearing base.

Further, the ratio of the outer diameter to the inner diameter of the bearing base is between 2 and 2.4.

Further, the corrugated foil is provided with at least one flow hole for connecting the regions on both sides of the corrugated foil.

In particular, the present invention also provides a centrifugal compressor comprising the gas bearing of any one of the above.

In the gas bearing of the present invention, since the corrugated foil is arranged between the bearing base and the top foil, the corrugated foil has a plurality of arched portions protruding toward the top foil, and the adhering surfaces of the arched portions are in surface contact. On the surface of the top foil, the friction area between the corrugated foil and the top foil is increased, thereby increasing the damping coefficient between the corrugated foil and the top foil, improving the supporting force and stability of the gas bearing, and prolonging its service life.

Further, in the gas bearing of the present invention, when the gas bearing is used as a radial bearing, the entire corrugated foil can also be arranged in a cylindrical shape, and is arranged between the bearing base and the top foil, and the corrugated foil is uniform along its circumferential direction. A plurality of arched parts are formed protruding toward the top foil, and the bonding surface of each arched part can be configured as a circular arc surface, which can realize the surface contact between the bonding surface and the top foil, and increase the number of arched parts. The contact area with the top foil improves the rigidity and compression resistance of the top foil; when the gas bearing is used as an axial bearing, the shape of the top foil is a flat plate, and the fitting surface of the arched part can also be appropriately set By forming a plane, the bonding surface and the top foil can be bonded in a surface-contact manner, which increases the contact area between the arch and the top foil, and improves the rigidity and compression resistance of the top foil.

The above and other objects, advantages and features of the present invention will be more apparent to those skilled in the art from the following detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of example and not limitation with reference to the accompanying drawings. The same reference numbers in the figures designate the same or similar parts or parts. It will be understood by those skilled in the art that the drawings are not necessarily to scale. In the attached picture:

1 is a schematic diagram of a complete machine structure of a centrifugal compressor according to an embodiment of the present invention;

Fig. 2 is a schematic cross-sectional view obtained by cutting the centrifugal compressor shown in Fig. 1 along the axial direction of the centrifugal impeller;

Fig. 3 is the enlarged view of A place of Fig. 2;

4 is a schematic diagram of a radial bearing in a centrifugal compressor according to an embodiment of the present invention;

Fig. 5 is the enlarged view at B of Fig. 4;

6 is a perspective view of an axial bearing in a centrifugal compressor according to an embodiment of the present invention;

7 is a side view of an axial bearing in a centrifugal compressor according to an embodiment of the present invention;

Fig. 8 is an enlarged view at C of Fig. 7;

9 is a schematic diagram of a corrugated foil in a radial bearing according to one embodiment of the present invention.

Detailed ways

Please refer to FIG. 1 to FIG. 3 , FIG. 1 is a schematic diagram of the whole machine structure of a centrifugal compressor according to an embodiment of the present invention, and FIG. 2 is a schematic diagram obtained by cutting the centrifugal compressor shown in FIG. 1 along the axial direction of the centrifugal impeller Fig. 3 is an enlarged view of part A of Fig. 2; the present invention first proposes a centrifugal compressor 1. The centrifugal compressor 1 may generally comprise a casing 10 , a motor 40 and at least one

compression unit

20 , 30 .

The casing 10 defines an accommodating space, and the motor 40 is installed in the casing 10 . The motor 40 includes a stator 41 and a rotor 42 , the stator 41 is fixed to the casing 10 , and the rotor 42 is rotatable relative to the stator 41 . The number of

compression units

20, 30 may be one or more. For example, the centrifugal compressor 1 may be a single-stage compression type, and only one compression unit may be provided. The centrifugal compressor 1 may also be of a multi-stage compression type in which a plurality of

compression units

20, 30 are provided. Each

compression unit

20 , 30 includes a volute 100 mounted to the casing 10 and a closed impeller 200 disposed within the volute 100 . The closed impeller 200 is configured to rotate under the driving of the motor 40 to compress the airflow entering the volute 100 and discharge it through the outlet of the volute 100 .

In some specific embodiments, such as shown in FIG. 1 and FIG. 2 , the centrifugal compressor 1 can be a two-stage compression type, and the number of compression units is two. It can be seen that one of the two

compression units

20 and 30 must be a low pressure stage and the other is a high pressure stage. As shown in FIG. 1 and FIG. 2 , the compression unit 20 on the left side of the drawing is the low pressure stage, and the compression unit 30 on the right side is the low pressure stage. for the high pressure level. The outlet of the volute 100 of the compression unit 20 of the low pressure stage communicates with the inlet of the volute 100 of the compression unit 30 of the high pressure stage through the connecting pipe 50 . Specifically, the inlet end of the connection pipe 50 is provided with a flange 51 to connect with the flange 60 of the outlet of the volute 100 of the compression unit 20 of the low pressure stage, and the outlet end of the connection pipe 50 is provided with a flange 52 to be connected to the outlet of the compression unit 30 of the high pressure stage. The volute 100 is connected. Preferably, the compression unit 20 of the low pressure stage and the compression unit 20 of the high pressure stage are located on both sides of the motor 40 in the axial direction, so that the closed impellers 200 of the two

compression units

20 and 30 are directly connected to the motor 40, and it is convenient for the two The axial force of the closed impeller 200 is partially offset.

The volute 100 defines an inlet flow channel 101, a scroll-shaped flow channel 102 and an outlet flow channel 103 which are connected in sequence along the airflow direction, that is, the flow channel of the volute 100 is divided into three sections. The inlet of the intake runner 101 constitutes the inlet of the volute 100 described herein, and the outlet of the outlet runner 103 constitutes the outlet of the volute 100 . The intake flow passage 101 extends in the axial direction (x-axis direction) of the closed impeller 200 .

Referring to FIGS. 2 and 3 , the centrifugal compressor may further include at least one radial bearing 70 and at least one axial bearing 80 . The radial bearing 70 and the axial bearing 80 are arranged in the casing 10 to support the motor 40 . The rotor 42, wherein the radial bearing 70 is used to limit the displacement of the rotor 42 in its radial direction, and the axial bearing 80 is used to limit the displacement of the rotor 42 in its axial direction.

In some embodiments, radial bearing 70 and axial bearing 80 may also be gas bearings. In the centrifugal compressor 1, the gas bearing can utilize the working fluid of the centrifugal compressor 1 as a lubricant. During operation, a gas film gap can be formed between the gas bearing and the rotor 42 , and the gas enters the gas film gap to form a dynamic pressure gas film, so that the rotor 42 is suspended. Compared with traditional sliding bearings, gas bearings have no mechanical contact, and the degree of wear is minimized, thereby ensuring that the accuracy is always stable; compared with magnetic bearings, gas bearings also have the advantages of simple structure and low manufacturing cost, especially when the centrifugal The compressor 1 is used in the field of refrigeration equipment (such as refrigerators, etc.), the gas bearing can use the gas refrigerant as a lubricant, and no additional lubricant is needed, so that the structure of the centrifugal compressor 1 is simple and compact, and at the same time, the rotation can be reduced. Process wear and prolong the service life of gas bearings.

Please refer to FIGS. 4 to 8 , FIG. 4 is a schematic diagram of a radial bearing in a centrifugal compressor according to an embodiment of the present invention; FIG. 5 is an enlarged view of part B of FIG. 4 ; A perspective view of an axial bearing in a compressor; FIG. 7 is a side view of an axial bearing in a centrifugal compressor according to an embodiment of the present invention; FIG. 8 is an enlarged view of C in FIG. 7 . In some embodiments, the gas bearing may further include a bearing base 110, a corrugated foil 120 and a top foil 130, the corrugated foil 120 is disposed between the bearing base 110 and the top foil 130, and the corrugated foil 120 further includes a plurality of spaced apart Each of the arched portions 122 has an adhering surface 122a facing the top foil 130 , and the adhering surface 122a is adhered to the surface of the top foil 130 in a surface-contact manner.

In this embodiment, the corrugated foil 120 is disposed between the bearing base 110 and the top foil 130 , so that the corrugated foil 120 can provide the top foil 130 with a supporting force away from the bearing base 110 , so that the gas bearing meets the strength of the centrifugal compressor 1 need. Specifically, the corrugated foil 120 is fixed on the bearing base 110 , and the corrugated foil 120 protrudes toward the top foil 130 to form a plurality of arched portions 122 , and the arched portions 122 can push up the top foil 130 in a direction away from the bearing base 110 . And the bonding surface 122a of the arched portion 122 is bonded to the surface of the top foil 130 in a surface contact manner, which increases the friction area between the corrugated foil 120 and the top foil 130, thereby increasing the friction between the corrugated foil 120 and the top foil 130. The damping coefficient improves the support force and stability of the gas bearing and prolongs its service life.

As mentioned in the background art section, the gas bearing in the prior art has a too small supporting surface, which may lead to unqualified strength of the gas bearing as a whole, resulting in abnormal vibration in actual operation, reducing the service life of the gas bearing, and it is difficult to Adapt to high-speed operation conditions.

Therefore, in order to overcome the defects of the prior art, the gas bearing of this embodiment uses the corrugated foil 120 to be attached to the surface of the top foil 130 in a surface-contact manner, so as to increase the friction area between the corrugated foil 120 and the top foil 130, so that in the During operation, the structure between the corrugated foil 120 and the top foil 130 is more stable, which improves the rigidity and compression resistance of the top foil 130 .

Referring to FIGS. 4 and 5 , in some embodiments, when the gas bearing is used as the radial bearing 70 , the shape of the bearing base 110 and the top foil 130 may be configured as a cylinder, and the diameter of the bearing base 110 is larger than that of the top foil 130, the top foil 130 is arranged at intervals inside the bearing base 110, the interior of the top foil 130 defines a space that can be used for the rotor 42 to pass through, and the rotor 42 can rotate relative to the top foil 130, and the top foil 130 and the rotor 42 form a space. In the air film gap, the gas enters the air film gap to form a dynamic pressure air film, so that the rotor 42 is suspended in the space, which can not only limit the radial displacement of the rotor 42, but also reduce the wear.

The corrugated foil 120 can also be configured in a cylindrical shape as a whole, and is disposed between the bearing base 110 and the top foil 130. The corrugated foil 120 is uniformly protruded toward the top foil 130 along its circumferential direction to form a plurality of arched portions 122, each of which is The adhering surface 122a of the arched portion 122 may be configured as a circular arc surface. In the radial bearing 70, the top foil 130 is cylindrical, and the attaching surface 122a is set to be the same arc surface as the outer circular surface of the top foil 130, so that the attaching surface 122a and the top foil 130 can be attached in a surface-contact manner. In combination, the contact area between the arched portion 122 and the top foil 130 is increased, and the rigidity and compression resistance of the top foil 130 are improved.

In some specific embodiments, when the gas bearing is used as the radial bearing 70 , the diameter of the abutting surface 122 a can also be configured to be smaller than or equal to the diameter of the top foil 130 , so as to ensure that the outer circumference of the abutting surface 122 a and the top foil 130 are There is no gap between the surfaces when they are attached.

4 and 5, in some embodiments, when the gas bearing is used as the radial bearing 70, the corrugated foil 120 extends in a trapezoidal wave shape in the circumferential direction of the gas bearing, and the corrugated foil 120 faces the top foil The trapezoidal top surface of 130 constitutes the contact surface 122a.

In this embodiment, since the entire corrugated foil 120 can also be configured in a cylindrical shape, the arched portion 122 is formed on the corrugated foil 120, so that the entire corrugated foil 120 has a trapezoidal wave shape and extends along the circumferential direction of the gas bearing, and the corrugated foil 120 faces The trapezoidal top surface of the top foil 130 constitutes the adhering surface 122a, and the two side surfaces of the arched portion 122 respectively extend from the two sides of the adhering surface 122a to the corrugated foil 120 to form a stable trapezoidal structure.

In some embodiments, when the gas bearing is used as the radial bearing 70, the diameter ratio of the top foil 130 to the bearing base 110 is between 0.8 and 1.2, eg, 0.8, 1, or 1.2, etc. After many experiments, the inventor realized that the above definition can make the gap between the top foil 130 and the bearing base 110 within a reasonable range, that is, the distance from the highest point to the lowest point of the corrugated foil 120 is limited, so that the gas bearing The structure is more reasonable and stable.

Referring to FIGS. 6 to 8 , in some embodiments, when the gas bearing is used as the axial bearing 80 , the shape of the top foil 130 can be configured as a flat plate, and the rotor 42 is formed with a thrust plate (not shown in the figure) along its radial direction. shown), the top foil 130 is opposite to one side of the thrust plate, a gas film gap is formed between the top foil 130 and the rotor 42, and the gas enters the gas film gap to form a dynamic pressure gas film, which can not only limit the radial displacement of the rotor 42, but also reduce the worn out.

In this embodiment, since the shape of the top foil 130 is a flat plate, the abutting surface 122a of the arched portion 122 can also be adapted to be flat, so that the abutting surface 122a and the top foil 130 are in surface contact with each other. In combination, the contact area between the arched portion 122 and the top foil 130 is increased, and the rigidity and compression resistance of the top foil 130 are improved.

Referring to FIGS. 6 to 8 , in particular, when the gas bearing is used as the axial bearing 80 , the bearing base 110 can also be configured as an annular flat plate, the inner ring of the bearing base 110 is used for the rotor 42 to pass through, and the top foil 130 is made to pass through. Opposite to the thrust plate of the rotor 42 . Preferably, top foils 130 are provided on both sides of a thrust disk to clamp the thrust disks of the rotor 42 , thereby limiting the axial displacement of the rotor 42 .

Referring to FIG. 7 and FIG. 8 , the corrugated foil 120 extends in a trapezoidal wave shape in the radial direction of the bearing base 110 , and the trapezoidal top surface of the corrugated foil 120 facing the top foil 130 forms a bonding surface 122 a. Since the arched portion 122 protrudes toward the top foil 130 , and the corrugated foil 120 extends in the radial direction of the bearing base 110 , the corrugated foil 120 has a trapezoidal wave shape in the radial direction of the bearing base 110 , and the arched portion 122 faces the top. The trapezoidal top surface of the foil 130 serves as the adhering surface 122a.

Referring to FIGS. 6 to 8 , when the gas bearing is used as the axial bearing 80 , the number of the top foils 130 is multiple, and correspondingly, the number of the corrugated foils 120 can be multiple, and the top foil 130 is along the circumferential direction of the bearing base 110 . The intervals are evenly arranged, and a gap is formed between two adjacent top foils 130 to facilitate the flow of lubricating gas.

In some embodiments, when the gas bearing is used as the axial bearing 80, the ratio of the outer diameter to the inner diameter of the bearing base 110 is between 2 and 2.4, such as 2, 2.2, or 2.4. The inventor realized after many experiments that the above-mentioned limitation can make the annular surface of the bearing base 110 be in a reasonable range, which is favorable for setting the corrugated foil 120 and the top foil 130, and makes the thrust of the top foil 130 and the rotor 42 possible. The relative area of the discs is within a reasonable range, which further ensures the rigidity and compression resistance of the top foil 130 .

Please refer to FIG. 9 , which is a schematic diagram of a corrugated foil in a radial bearing according to an embodiment of the present invention. In some embodiments, the corrugated foil 120 is provided with at least one flow hole 124 for connecting regions on both sides of the corrugated foil 120 .

In this embodiment, the bearing base 110 may also be provided with a plurality of air inlet holes (not shown in the figure) for guiding the lubricating gas from the air inlet holes to the gap between the bearing base 110 and the top foil 130, When the lubricating gas fills the gap, the lubricating gas can directly act on the corrugated foil 120 between the bearing base 110 and the top foil 130 , thereby further improving the stiffness of the corrugated foil 120 . The corrugated foil 120 is also provided with a circulation hole 124. The circulation hole 124 communicates with the regions on both sides of the corrugated foil 120. The lubricating gas on one side of the corrugated foil 120 can flow to the other side of the corrugated foil 120 through the circulation hole 124, so that the lubricating gas can flow to the other side of the corrugated foil 120. The better flow in the gas bearing prevents the rotor 42 from contacting the gas bearing, avoids the wear of the gas bearing after contact, and ensures that the rotor 42 can run at high speed.

By now, those skilled in the art will recognize that although various exemplary embodiments of the present invention have been shown and described in detail herein, the present invention may still be implemented in accordance with the present disclosure without departing from the spirit and scope of the present invention. The content directly determines or derives many other variations or modifications consistent with the principles of the invention. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

A gas bearing, characterized by comprising:

A bearing base, a top foil, and a corrugated foil disposed between the bearing base and the top foil; wherein,

The corrugated foil includes a plurality of arched portions arranged at intervals, and each of the arched portions has an adhering surface facing the top foil, and the adhering surface is adhered to the top foil in a surface-contact manner surface.
The gas bearing of claim 1, wherein:

The gas bearing is a radial bearing, and the wave foil is cylindrical as a whole; and

The abutting surface of each of the arched portions is a circular arc surface that matches the shape of the outer circular surface of the top foil.
The gas bearing of claim 2, wherein:

The corrugated foil extends in a trapezoidal wave shape in the circumferential direction of the gas bearing, and a trapezoidal top surface of the corrugated foil facing the top foil constitutes the bonding surface.
The gas bearing of claim 2, wherein:

The top foil to the bearing base diameter ratio is between 0.8 and 1.2.
The gas bearing of claim 1, wherein:

The gas bearing is an axial bearing, and the top foil is a flat plate as a whole; and

The abutting surface of each of the arched portions is flat.
The gas bearing of claim 5, wherein:

The bearing base is in the shape of an annular flat plate;

The corrugated foil extends in a trapezoidal wave shape in the radial direction of the bearing base, and the trapezoidal top surface of the corrugated foil facing the top foil constitutes the bonding surface.
The gas bearing of claim 6, wherein:

The top foils are plural in number and evenly spaced along the circumferential direction of the bearing base.
The gas bearing of claim 6, wherein:

The ratio of the outer diameter to the inner diameter of the bearing base is between 2 and 2.4.
The gas bearing of claim 1, wherein:

The corrugated foil is provided with at least one flow hole for connecting the regions on both sides of the corrugated foil.
A centrifugal compressor, characterized by comprising the gas bearing according to any one of claims 1 to 9.