CN109899303B - A Small Micro Centrifugal Compressor Without Radial Bearings - Google Patents

Abstract

The invention discloses a small and micro centrifugal compressor without radial bearings, which relates to the technical field of compressor design, comprising: a casing; an air flow hole in a main shaft that communicates with an exhaust port of the casing; a first axial static The ring and the inner bottom of the casing form a cavity, and the first axial static ring has at least two ventilation holes A along the circumference; the first moving ring is fixedly arranged on the main shaft; the rotating sleeve is fixedly arranged on the outer surface of the rotor; The sleeve is fixedly arranged on the inner surface of the stator; the second moving ring is fixedly arranged on the main shaft; the second axial static ring is fixedly arranged in the casing; the inlet and exhaust ports of the centrifugal impeller are respectively arranged opposite to the inlet and exhaust ports of the casing . The beneficial effect of the invention is that it is not necessary to install radial and axial thrust bearings, the compressor is completely oil-free, and no lubrication system is required, so that the structure of the compressor is simpler and more compact, which is beneficial to the miniaturization of the compressor; The channel takes away the heat generated in the working process of the motor, which has the effect of internal circulation cooling.

Description

A Small Micro Centrifugal Compressor Without Radial Bearings

technical field

The invention relates to the technical field of compressor design, in particular to a small and micro centrifugal compressor without radial bearings.

Background technique

With the development of electronic technologies such as integrated circuits, the heat flux density of modern high heat flux devices is increasing. Passive cooling methods cannot meet the heat dissipation requirements. A refrigeration system is required to ensure the normal operation of the electronic system. Due to the limitation of space and weight in many occasions such as mobile or portable electronic systems, chip cooling, radar cooling, and defense and military industries, lightweight, small and miniature refrigeration systems are urgently needed.

The compressor is the core key equipment of the refrigeration system. As a rotary turbomachine, the centrifugal compressor has the advantages of compact and simple structure, high efficiency and reliability, and long service life. It is an ideal small and micro compressor model. However, in order to obtain a high discharge pressure for a small and micro centrifugal compressor to meet the requirements of the refrigeration system, it is necessary to increase the compressor speed and reduce the leakage of the shaft end seal. The current technology cannot meet these requirements.

At present, there are mainly two types of small and micro compressors: rolling rotor type and linear piston type, and the principle is completely different from that of centrifugal compressors. At present, high-speed centrifugal compressors supported by magnetic suspension bearings and gas bearings cannot be small and miniature. The magnetic suspension bearing has a complex structure and requires a separate control system. The static pressure gas bearing needs an independent compressed air source for gas supply. Limited; the structure of the dynamic pressure gas bearing is complex, the requirements for materials and processing technology are very high, and the reliability and service life cannot be guaranteed. In addition, the technical problem of the shaft end seal of the compressor is also a bottleneck restricting the development of the centrifugal compressor to the miniaturization. Centrifugal compressor technology has not been able to meet the requirements of small and micro refrigeration systems.

The working principle of the rolling rotor compressor and the linear piston compressor determines that further miniaturization cannot be achieved, and the operating efficiency of these two compressors is low. There are wearing parts in the parts, which need to be replaced regularly, and the reliability and life cannot be guaranteed. .

The centrifugal compressor has a simple structure, no easily damaged parts, high reliability and long service life. However, the centrifugal compressor can only be miniaturized by high speed. The existing magnetic bearing, gas bearing and sealing technology cannot achieve the ultra-high-speed miniaturization of the centrifugal compressor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to design a small and micro centrifugal compressor without radial bearing in order to solve the high-speed bearing and gas sealing technology.

In order to achieve the above purpose, the technical solution of the present invention is a small and micro centrifugal compressor without radial bearing, comprising: a casing, which is provided with an air inlet and an exhaust port; a main shaft, which is rotatably arranged on the casing Inside the body, the main shaft is provided with an air flow hole that communicates with the exhaust port of the casing; a first axial static ring is fixedly arranged in the casing, and the first axial static ring is connected to the casing A cavity is formed in the inner bottom of the first axial static ring, and at least two ventilation holes A are opened along the circumference of the first axial static ring; the first moving ring is fixedly arranged on the main shaft and is located outside the first axial static ring ; the rotor is fixedly arranged on the main shaft and is located on the outer side of the first moving ring; the rotating sleeve is fixedly arranged on the outer surface of the rotor; the stator is fixedly arranged in the casing and is opposite to the rotor A fixed sleeve is fixedly arranged on the inner surface of the stator; a second moving ring is fixedly arranged on the main shaft and is located outside the rotor; a second axial static ring is fixedly arranged in the casing , located on the second moving ring, located in the casing, and located outside the first axial static ring, the air inlet of the centrifugal impeller is opposite to the air inlet of the casing, the discharge port of the centrifugal impeller The air port is arranged opposite to the housing exhaust port; wherein, the first axial static ring and the first moving ring form a first channel, the rotating sleeve and the fixed sleeve form a second channel, and the first The second moving ring and the second axial static ring form a third channel, the second axial static ring and the centrifugal impeller form a fourth channel; the exhaust port of the centrifugal impeller communicates with the ventilation hole B through the fourth channel, so The vent hole B communicates with the vent hole A after passing through the third channel and the second channel, and the vent hole A communicates with the air flow hole after passing through the cavity.

Further, a radial static ring is also included, and the radial static ring is fixedly arranged on the housing and located outside the second dynamic ring.

Still further, the gap between the radial static ring and the second dynamic ring is larger than the gap between the main shaft and the first axial static ring.

Still further, the gap between the radial static ring and the second dynamic ring is larger than the gap between the main shaft and the second axial static ring.

Further, the second axial static ring is provided with a vent hole B along the circumference, the outer diameter of the second axial static ring is D4, and the diameter of the center of the vent hole B is D5,

Still further, the first axial static ring has two ventilation holes A along the circumference, the outer diameter of the first axial static ring is D1, and the diameter of the center of the outer ventilation hole A is D2. , the vent hole on the inside is D3,

Further, the end surfaces and the cylindrical surfaces of the first moving ring and the second moving ring are provided with dynamic pressure grooves.

Further, the casing includes a casing and a base, the centrifugal impeller is disposed in the casing, and the second axial static ring is disposed in the base.

Further, the first moving ring and the second moving ring are both made of cemented carbide.

Still further, the hardness of the material of the first axial static ring and the second axial static ring is lower than that of the first moving ring and the second moving ring.

The beneficial effects of the present invention are:

1. There is no need to install radial and axial thrust bearings, the compressor is completely oil-free, and no lubrication system is required, which makes the structure of the compressor simpler and more compact, which is conducive to the miniaturization of the compressor;

2. An air film support is formed between the moving ring and the static ring. When the rotating sleeve rotates, a dynamic pressure effect is generated between the stationary sleeve to form an air film, which balances the axial load and radial load of the compressor rotor to make the compressor The rotor is in the state of air suspension, there is no friction loss of solid contact, and the compressor can reach ultra-high speed;

3. The air circulation channel takes away the heat generated in the working process of the motor, which has the effect of internal circulation cooling.

Description of drawings

FIG. 1 is a schematic structural diagram of the compressor of the present application.

In the above figures, 1. shell; 11. outer shell; 12. base; 2. main shaft; 21. air flow hole; 3. first axial static ring; 31. ventilation hole A; 4. first moving ring; 5. Rotor; 51. Rotating sleeve; 6. Stator; 61. Fixed sleeve; 7. Second moving ring; 8. Second axial static ring; 81. Ventilation hole B;

Detailed ways

In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, below in conjunction with the accompanying drawings and preferred embodiments, the specific embodiments, structures, features and effects according to the present invention are described in detail as follows:

A small and micro centrifugal compressor without radial bearing, as shown in Figure 1, includes a casing 1, a main shaft 2, a first axial static ring 3, a first moving ring 4, a rotor 5, a rotating sleeve 51, and a stator 6. Fixed sleeve 61 , second moving ring 7 , second axial static ring 8 and centrifugal impeller 9 .

The casing 1 of the compressor is provided with an intake port and an exhaust port. The main shaft 2 is rotatably arranged in the casing 1 , and an air flow hole 21 is opened in the main shaft 2 . The first axial static ring 3 is fixedly arranged in the housing 1, the first axial static ring 3 is located in the housing 1, the first axial static ring 3 and the inner bottom of the housing 1 form a cavity, the first shaft Two weeks of ventilation holes A31 are opened to the static ring 3 along the circumference. The first moving ring 4 is fixedly arranged on the main shaft 2 , and the first moving ring 4 is located outside the first axial stationary ring 3 .

The rotor 5 is fixedly arranged on the main shaft 2 , the stator 6 is fixedly arranged in the casing 1 , both the rotor 5 and the stator 6 are arranged in the casing 1 , and the stator 6 is arranged opposite to the rotor 5 . The rotating sleeve 51 is fixedly arranged on the outer surface of the rotor 5 , and the stationary sleeve 61 is fixedly arranged on the inner surface of the stator 6 .

The second moving ring 7 is fixedly arranged on the main shaft 2 , and the second moving ring 7 is located outside the rotor 5 . Preferably, the radial static ring 71 is fixedly arranged on the housing 1 , and the radial static ring 71 is located outside the second moving ring 7 . The second axial static ring 8 is fixedly arranged in the housing 1 , the second axial static ring 8 is located outside the second dynamic ring 7 , and the second axial static ring 8 is provided with a vent hole B81 along the circumference.

The centrifugal impeller 9 is fixedly arranged on the main shaft 2 , the centrifugal impeller 9 is arranged in the casing 1 , and the centrifugal impeller 9 is located outside the second axial stationary ring 8 . The inlet and exhaust ports of the centrifugal impeller 9 are respectively arranged opposite to the inlet and exhaust ports of the casing 1 . Most of the gas enters the compressor cavity from the air inlet of the casing 1, and is discharged from the exhaust port of the casing 1 after the centrifugal impeller 9 increases the speed and pressure.

The first axial stationary ring 3 and the first moving ring 4 form a first channel, and the first channel is a small clearance channel. The rotating sleeve 51 and the stationary sleeve 61 form a second channel. The second moving ring 7 and the second axial stationary ring 8 form a third channel, and the third channel is a small clearance channel. The second axial stationary ring 8 and the centrifugal impeller 9 form a fourth channel, and the fourth channel is a small clearance channel. The exhaust port of the centrifugal impeller 9 communicates with the vent hole B81 through the fourth channel, the vent hole B81 communicates with the vent hole A31 after passing through the third channel and the second channel, and the vent hole A31 communicates with the air flow hole 21 after passing through the cavity.

During use, the rotor 5 drives the main shaft 2 to rotate, the first moving ring 4, the second moving ring 7 and the centrifugal impeller 9 rotate together with the main shaft 2. After a small amount of gas flows out from the exhaust port of the centrifugal impeller 9, it will directly enter In the fourth channel, and then into the third channel through the vent hole B81, the gas pressure near the radial static ring 71 will gradually increase during the rotation process, and then flow into the second channel, and then flow into the first channel and Enter into the cavity between the first axial static ring 3 and the inner bottom of the casing 1 from the outer vent hole A31, and a part of the gas enters between the static ring 3 and the moving ring 4 through the inner vent hole A31, and the rotational pressure of the follower ring It rises and flows out from the outer vent hole A31. Since the main shaft 2 has an air flow hole 21, the air flow will flow from the air flow hole 21 to the air inlet of the housing 1. The above flow process is an air circulation channel. The airflow channel can take away the heat generated in the working process of the motor, and has the effect of internal circulation cooling.

During the rotation of the first moving ring 4 and the second moving ring 7 with the main shaft 2 , the upper and lower end surfaces and the circumferential cylindrical surface of the first moving ring 4 and the second moving ring 7 are respectively connected to the inner wall of the housing 1 and the radial static A dynamic pressure effect will be generated between the surfaces of the rings 71 to form a gas film. In order to improve the dynamic pressure effect, dynamic pressure grooves are formed on the end faces and cylindrical surfaces of the first moving ring 4 and the second moving ring 7 . When the rotating sleeve 51 of the motor rotates and the stationary sleeve 61, a dynamic pressure effect will also be generated to form an air film, so that the compressor rotor is also in a suspended state in the radial direction, and the radial gap is automatically balanced and adjusted. The air film makes the compressor rotor system (including the rotating shaft 2, the motor rotor 3, the moving ring 7, the centrifugal impeller 9) in a suspended state, without the friction loss of solid contact, and can achieve ultra-high speed, and the pressure of the air film is higher than that of the rotor 5. The pressure in the cavity achieves a sealing effect similar to dry gas sealing; the compressor adopts a fully enclosed structure with only one intake port and exhaust port, no other lubrication and cooling system is required, and the external leakage of the shaft end is avoided, that is, there is no external leakage. leakage.

第一轴向静环沿圆周开有两周通气孔，静环的外径为D1，外侧通气孔的圆心所在的直径为D2，内侧通气孔为D3，

该设计能够稳定气膜的形成。Preferably, the outer diameter of the second axial static ring 8 is D4, the diameter of the center of the vent hole B81 is D5,

The first axial static ring has two ventilation holes along the circumference. The outer diameter of the static ring is D1, the diameter of the center of the outer ventilation hole is D2, and the inner ventilation hole is D3.

This design can stabilize the formation of the gas film.

In addition, the gap between the radial static ring 71 and the second dynamic ring 7 is larger than the gap between the main shaft 2 and the first axial static ring 3; the gap between the radial static ring 71 and the second dynamic ring 7 is larger than the main shaft 2 and the second axial static ring 8, this design prevents the second moving ring 7 from impacting the radial static ring 71.

The casing 1 includes a casing 11 and a base 12. The centrifugal impeller 9 is arranged in the casing 11, and the second axial static ring 8 is arranged in the base 12. The design is convenient for installing the compressor.

During startup or shutdown of the compressor, the first axial static ring 3 and the first moving ring 4, as well as the second moving ring 7 and the second axial static ring 8 will rub briefly. The ring material is soft and hard, the first moving ring 4 and the second moving ring 7 are made of cemented carbide, and the hardness of the first axial static ring 3 and the second axial static ring 8 is lower than that of the first moving ring 4 and the second moving ring. Two moving rings 7 are sprayed on the surfaces of the first axial static ring 3, the first moving ring 4, the second moving ring 7 and the second axial static ring 8 to improve the lubricating performance and wear resistance of the surfaces.

The present invention has been described above with reference to preferred embodiments, but the scope of protection of the present invention is not limited thereto, and various improvements may be made and equivalents may be substituted therein without departing from the scope of the present invention. As long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way, and any reference signs in the claims should not be construed as limiting the claims involved, regardless of In all respects, the embodiments should be considered as exemplary and not restrictive. Therefore, any technical solutions falling within the scope of the claims are within the protection scope of the present invention.

Claims (8)

1. A miniature centrifugal compressor without radial bearings, comprising:

a housing (1) provided with an air inlet and an air outlet;

the main shaft (2) is rotatably arranged in the shell (1), and an airflow through hole (21) communicated with an exhaust port of the shell (1) is formed in the main shaft (2);

the first axial static ring (3) is fixedly arranged in the shell (1), a cavity is formed by the first axial static ring (3) and the inner bottom of the shell (1), and at least two circumferential vent holes A (31) are formed in the first axial static ring (3) along the circumference;

the first movable ring (4) is fixedly arranged on the main shaft (2) and is positioned on the upper side of the first axial static ring (3);

the motor rotor (5) is fixedly arranged on the main shaft (2) and is positioned on the upper side of the first movable ring (4);

a rotating sleeve (51) fixedly arranged on the outer surface of the rotor (5);

the motor stator (6) is fixedly arranged in the shell (1) and is opposite to the rotor (5);

a stationary sleeve (61) fixedly provided on an inner surface of the stator (6);

the second rotating ring (7) is fixedly arranged on the main shaft (2) and is positioned on the upper side of the rotor (5);

the second axial static ring (8) is fixedly arranged in the shell (1) and is positioned on the upper side of the second movable ring (7), and at least one circle of vent holes B (81) are formed in the second axial static ring (8) along the circumference;

the centrifugal impeller (9) is fixedly arranged on the main shaft (2), is positioned in the shell (1) and is positioned on the upper side of the second axial static ring (8), the air inlet of the centrifugal impeller (9) is arranged opposite to the air inlet of the shell (1), and the air outlet of the centrifugal impeller (9) is arranged opposite to the air outlet of the shell (1);

wherein the first axial static ring (3) and the first rotating ring (4) form a first channel, the rotating sleeve (51) and the fixed sleeve (61) form a second channel, the second rotating ring (7) and the second axial static ring (8) form a third channel, and the second axial static ring (8) and the centrifugal impeller (9) form a fourth channel; an air outlet of the centrifugal impeller (9) is communicated with an air vent B (81) through a fourth channel, the air vent B (81) is communicated with an air vent A (31) through a third channel and a second channel, and the air vent A (31) is communicated with an air flow through hole (21) through a cavity;

the outer diameter of the second axial static ring (8) is D4, the diameter of the circle center of the vent hole B (81) is D5,

the outer diameter of the first axial static ring (3) is D1, the vent hole A comprises an outer vent hole and an inner vent hole, the diameter of the center of the outer vent hole is D2, the diameter of the center of the inner vent hole is D3,

2. the miniature centrifugal compressor without radial bearing according to claim 1, further comprising a radial stationary ring (71), wherein said radial stationary ring (71) is fixedly disposed on said housing (1) outside said second rotating ring (7).

3. Small centrifugal compressor without radial bearing, according to claim 2, characterized in that the clearance between the radial static ring (71) and the second rotating ring (7) is greater than the clearance between the main shaft (2) and the first axial static ring (3).

4. Small centrifugal compressor without radial bearing, according to claim 2, characterized in that the clearance between the radial static ring (71) and the second rotating ring (7) is greater than the clearance between the main shaft (2) and the second axial static ring (8).

5. The small mini centrifugal compressor without radial bearing according to claim 1, characterized in that the end surface and the cylindrical surface of the first rotating ring (4) and the second rotating ring (7) are both provided with dynamic pressure grooves.

6. A small mini centrifugal compressor without radial bearing according to claim 1, characterized in that the casing (1) comprises a casing (11) and a seat (12), the centrifugal impeller (9) being arranged in the casing (11), the second axial stationary ring (8) being arranged in the seat (12).

7. Small centrifugal compressor without radial bearing, according to claim 1, characterized in that said first rotating ring (4) and said second rotating ring (7) are made of cemented carbide.

8. Small micro centrifugal compressor without radial bearing, according to claim 1 or 7, characterized by the fact that the first (3) and second (8) axial static rings are made of a material with a lower hardness than the first (4) and second (7) moving rings.

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