CN216599245U

CN216599245U - Air compressor cooling structure and air compressor

Info

Publication number: CN216599245U
Application number: CN202123268543.6U
Authority: CN
Inventors: 陈彬; 廖繁林; 闫瑾; 苏久展; 陈嘉星; 蔡由俊
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2022-05-24
Anticipated expiration: 2031-12-23

Abstract

The utility model provides an air compressor cooling structure, air compressor cooling structure wherein, which comprises a housing, be equipped with electric motor rotor in the casing, electric motor rotor includes the edge second minor axis and the first minor axis that electric motor rotor's axial interval set up, be provided with the thrust dish that corresponds with air supporting axial bearing on the second minor axis, the axle head of first minor axis is connected with first impeller, be constructed first cooling air flue on the casing, be constructed in the first minor axis and have the through-flow runner, the outside cooling air flow via of casing first cooling air flue reaches discharge behind the through-flow runner the outside of casing. According to the utility model discloses, can be right first minor axis and being in the magnet steel of first minor axis one end cools off the heat dissipation, can reduce electric motor rotor's temperature rise improves the anti demagnetization ability of magnet steel, reduces whole axle length deflection, prevents that first impeller is cut to pieces and is rubbed the phenomenon that the volute leads to the complete machine to become invalid and take place.

Description

Air compressor cooling structure and air compressor

Technical Field

The utility model belongs to the technical field of the compressor, concretely relates to air compressor cooling structure, air compressor.

Background

The conventional air suspension centrifugal two-stage air compressor comprises a first-stage volute, a first-stage impeller, a second-stage volute, a second-stage impeller, a first-stage diffuser, a second-stage diffuser, a front end cover, a rear end cover, a water-cooling shell, a permanent magnet motor stator, a permanent magnet motor rotor, an air-floatation axial bearing assembly, an air-floatation radial bearing assembly and the like.

Wherein: the permanent magnet motor rotor comprises a front short shaft, a rear short shaft, magnetic steel and a sheath (made of alloy/carbon fiber materials); the water cooling shell is provided with a cooling water channel, which is usually a spiral water channel or an axial U-shaped water channel; the clearance between the secondary impeller and the secondary volute is the blade top clearance delta, wherein delta mainly influences the aerodynamic efficiency, and the larger delta is, the lower the aerodynamic efficiency is.

The prior art structure mainly has the following difficulties:

1. cannot effectively cool the rotor

The high-speed permanent magnet motor has the characteristics of high rotating speed, small volume and high efficiency, and the conventional centrifugal air compressor usually adopts the high-speed permanent magnet motor. The motor stator cools and radiates heat through a cooling water channel on the shell, but the motor rotor does not cool independently and effectively, and can radiate heat outwards from the stator only in a heat radiation mode. The high-speed permanent magnet motor is different from the traditional motor in frequency and volume, the magnetic steel and the sheath (when a metal sheath is adopted) are heated seriously due to current high-frequency harmonic waves, if the carbon fiber sheath is adopted, the heat generated by the magnetic steel is more difficult to radiate outwards, and meanwhile, the radiating condition is more difficult due to the small volume of the whole machine. To sum up, the rotor temperature rise is more serious when the high-speed motor runs, and the higher temperature rise can cause the performance reduction of the magnetic steel demagnetization motor, and even causes the failure of the sheath to cause danger. Therefore, how to effectively cool the rotor is the key point of the structural design of the air compressor.

2. The axial extension of the rotor causes the abrasion of the impeller and the volute

High-speed motors are usually matched with special bearings, such as magnetic suspension bearings, air suspension bearings, sliding bearings and the like, and the bearings are different from traditional ball bearings in that the traditional ball bearings are respectively arranged on two sides of a rotor to limit the radial direction and the axial direction of the rotor. However, for the above-mentioned special bearing, the radial bearing can realize the radial position limitation of the rotor, but the axial bearing is only arranged on one side for the axial position limitation, when the temperature rise of the rotor is high, the whole shaft deforms and extends towards two ends by taking the thrust disc (due to the position limitation reason) as the center, according to the material thermal deformation formula: where σ denotes a thermal deformation amount, α denotes a thermal expansion coefficient, and Δ T denotes a temperature rise. The distance L2 between the secondary impeller side and the thrust disc is far larger than the distance L1 between the primary impeller side and the thrust disc, and when the temperature of the rotor rises by combining the formula, the thermal deformation amount between the thrust disc and the secondary impeller side is far larger than that between the thrust disc and the secondary impeller side, and the blade top gap delta between the secondary impeller and the volute becomes smaller. If the cooling effect of the rotor is poor, the tip clearance delta is reduced sharply, and the impeller and the volute are scratched seriously to cause abnormal or damaged performance of the whole machine. If the design value of delta is increased to prevent the scraping, the pneumatic efficiency of the air compressor in a low rotating speed area is seriously reduced (because the temperature rise of the rotor is increased along with the increase of the operating rotating speed), the temperature rise of the rotor in the low rotating speed area is not obvious, and the efficiency of the whole air compressor is reduced due to the larger blade top clearance.

SUMMERY OF THE UTILITY MODEL

Therefore, the utility model provides an air compressor cooling structure, air compressor can overcome among the prior art air compressor because the single-ended axial positioning of pivot, the pivot shaft stretch out and warp great lead to the blade top clearance sharply to reduce when cooling is bad to electric motor rotor especially pivot, probably leads to impeller and volute to take place to cut to the right and lead to rubbing the complete machine performance unusual damage not enough even.

In order to solve the problem, the utility model provides an air compressor cooling structure, which comprises a housing, be equipped with electric motor rotor in the casing, electric motor rotor includes the edge second minor axis and the first minor axis that electric motor rotor's axial interval set up, be provided with the thrust dish that corresponds with air supporting axial bearing on the second minor axis, the axle head of first minor axis is connected with first impeller, be constructed first cooling air flue on the casing, it has the through-flow runner to construct in the first minor axis, the outside cooling air current via of casing first cooling air flue reaches discharge behind the through-flow runner the outside of casing.

In some embodiments, the first stub shaft is rotatably supported on a first end cap provided at the first end of the housing, and the first end cap is configured with a second cooling air passage through which the cooling air flow in the first cooling air passage can enter the through-flow passage.

In some embodiments, a first diffuser is connected to a side of the first end cap facing the first impeller, and a third cooling air passage is configured on the first diffuser, and the cooling air flow in the second cooling air passage can enter the through-flow passage through the third cooling air passage.

In some embodiments, the first stub shaft has a shoulder annulus facing a side of the first impeller, the first diffuser has an axial boss extending toward the shoulder annulus, the inlet of the through-flow passage is located on the shoulder annulus, the outlet of the third cooling air passage is located on the axial boss, and the outlet of the third cooling air passage and the inlet of the through-flow passage are axially alignable with each other in the axial direction of the electric machine rotor.

In some embodiments, the first diffuser is made of an abrasion-resistant material.

In some embodiments, an amount of clearance of an axial gap formed between the axial boss and the collar land is δ 1, a tip clearance of the first impeller is δ, δ 1 < δ.

In some embodiments, δ - δ 1 > 0.15 mm.

In some embodiments, a magnetic steel is sandwiched between the second stub shaft and the first stub shaft, and the through-flow channel has a channel segment disposed adjacent to the magnetic steel; and/or the circulation path of the through flow channel is U-shaped or V-shaped; and/or the through-flow channel has a plurality of through-flow channels.

In some embodiments, a lubricating coating is provided on the outer circumferential wall of the first stub shaft in a region corresponding to the air bearing journal; and/or a second impeller is connected to the end part of the second short shaft; and/or a cooling water channel is formed on the machine shell.

The utility model also provides an air compressor, including foretell air compressor cooling structure.

The utility model provides a pair of air compressor cooling structure, air compressor through construct on first minor axis the through-flow runner, thereby make cooling airflow in the first cooling air flue can get into inside the first minor axis, thereby can be right first minor axis and being in the magnet steel of first minor axis one end dispels the heat the cooling, can reduce electric motor rotor's temperature rise improves the anti demagnetization ability of magnet steel, reduces whole axle length deflection, prevents that first impeller from cutting the phenomenon of rubbing the volute and leading to the complete machine to become invalid and taking place.

Drawings

Fig. 1 is a schematic view of an internal structure of a cooling structure of an air compressor according to an embodiment of the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is an enlarged view of a portion of FIG. 1 at B;

FIG. 4 is a perspective view of the first stub shaft of FIG. 1;

fig. 5 is a schematic diagram of an internal structure of a cooling structure of an air compressor according to another embodiment of the present invention.

The reference numerals are represented as:

101. a first stage volute; 102. a second impeller; 103. a secondary volute; 104. a first impeller; 105. a second diffuser; 106. a first diffuser; 1061. an axial boss; 107. a second end cap; 108. a first end cap; 109. a housing; 110. a motor stator; 111. a motor rotor; 112. an air-floating axial bearing; 113. an air-floating radial bearing; 114. a thrust plate; 115. a second minor axis; 116. a first minor axis; 117. magnetic steel; 118. sheath (alloy/carbon fiber material); 119. a cooling water channel; 201. a through-flow channel; 202. a first cooling air duct; 2021. a second cooling air duct; 2022. and a third cooling air channel.

Detailed Description

Referring to fig. 1 to 5 in combination, according to an embodiment of the present invention, there is provided an air compressor cooling structure, including a housing 109, a motor rotor 111 is disposed in the housing 109, the motor rotor 111 includes a second stub shaft 115 and a first stub shaft 116 disposed along an axial direction of the motor rotor 111 at intervals, a thrust disk 114 corresponding to an air flotation axial bearing 112 is disposed on the second stub shaft 115, a first impeller 104 is connected to a shaft end of the first stub shaft 116, a first cooling air passage 202 is configured on the housing 109, a through flow passage 201 is configured in the first stub shaft 116, and a cooling air flow outside the housing 109 is discharged outside the housing 109 through the first cooling air passage 202 and the through flow passage 201. In this technical scheme, through constructing on first minor axis 116 through flow channel 201, thereby make cooling air flow in the first cooling air flue 202 can get into inside first minor axis 116, thereby can be right first minor axis 116 and being in the magnet steel 117 of first minor axis 116 one end is dispelled the heat and is cooled, can reduce electric motor rotor 111's temperature rise improves the anti demagnetization ability of magnet steel 117 (for example, the permanent magnet), reduces whole axle length deflection, prevents that first impeller 104 from cutting the phenomenon of rubbing the volute and leading to the complete machine to become invalid and takes place. It can be understood that, because the whole-axis elongation is reduced, a large design margin is not required to be given when the aerodynamic tip clearance is designed (the factors of assembly tolerance stack and whole-axis thermal elongation are considered in the design of the tip clearance generally), so that the aerodynamic efficiency can be effectively improved.

The first stub shaft 116 is rotatably supported (specifically, by an air-bearing radial bearing 113) on a first end cap 108, the first end cap 108 is disposed at a first end of the casing 109, a second cooling air passage 2021 is configured on the first end cap 108, a cooling air flow in the first cooling air passage 202 can enter the through-flow passage 201 via the second cooling air passage 2021, and the first end cap 108 can be cooled by the cooling air flow. Furthermore, a first diffuser 106 is connected to a side of the first end cap 108 facing the first impeller 104, a third cooling air passage 2022 is configured on the first diffuser 106, and the cooling air flow in the second cooling air passage 2021 can enter the through-flow passage 201 via the third cooling air passage 2022, so that the first diffuser 106 can be further cooled.

In some embodiments, the first stub shaft 116 has a shaft shoulder ring surface facing the first impeller 104, the first diffuser 106 has an axial boss 1061 extending toward the shaft shoulder ring surface, the inlet of the through-flow passage is located on the shaft shoulder ring surface, the outlet of the third cooling air passage 2022 is located on the axial boss 1061, and the outlet of the third cooling air passage 2022 and the inlet of the through-flow passage 201 can be aligned in the axial direction of the electric machine rotor 111, so that the cooling air flow in the third cooling air passage 2022 can more easily enter the through-flow passage 201.

The first diffuser 106 is made of an abrasion-resistant material so as to enhance the abrasion resistance of the first diffuser 106 and prolong the service life of the first diffuser.

In some embodiments, the clearance amount of the axial clearance formed between the axial boss 1061 and the shaft shoulder ring boss is δ 1, the tip clearance of the first impeller 104 is δ, δ 1 is smaller than δ, and specifically, δ - δ 1 is greater than 0.15mm, in this technical scheme, when the elongation of the rotor is still greater than the tip clearance δ after the rotor is cooled in an extremely harsh operating environment of the air compressor, since δ 1 is set slightly smaller than the tip clearance δ, and the diffuser is made of an abrasion-resistant material, the protection of the first impeller 104 on the corresponding secondary volute can be realized; otherwise, the aerodynamic performance of the first impeller 104 and the volute can be rapidly reduced and the whole machine can be scrapped after the first impeller and the volute are worn, and the wear of the first diffuser 106 and the shaft can not affect the performance of the air compressor.

The through-flow channel 201 has a channel section disposed adjacent to the magnetic steel 117 to sufficiently dissipate heat and cool the magnetic steel 117, the through-flow channel 201 has a U-shaped (as shown in fig. 4) or V-shaped, preferably U-shaped, so as to have a channel section parallel to the radial direction of the magnetic steel 117 to ensure sufficient cooling of the magnetic steel 117 by the cooling airflow, it can be understood that the two connected channel sections should be connected in an arc channel manner to reduce energy loss of the cooling airflow and further improve the cooling effect, and fig. 5 shows a through-flow channel 201 of a right-angled bent structure, which causes a larger energy loss to the cooling airflow compared with the aforementioned U-shaped, but can also be applied in some cases; the through-flow passages 201 are arranged at intervals along the circumferential direction of the first short shaft 116, so that the cooling air flow in the third cooling air passage 2022 can smoothly enter.

In some embodiments, a lubrication coating is disposed on an area of the outer circumferential wall of the first stub shaft 116 corresponding to the air-floatation radial bearing 113, the lubrication coating is specifically a lubrication coating made of an organic polymer material, which is sensitive to temperature, and high temperature may cause the coating to fail, and ultimately result in a bearing life, in the technical solution of the present invention, as shown in fig. 3 (the arrow in the figure indicates cooling airflow), since a gap δ 1 exists between the first diffuser 106 and the first stub shaft 116, most of the cooling air flowing out from the first diffuser 106 enters the through-flow channel 201 in the first stub shaft 116, but a part of the cooling air still passes through the bearing working air gap between the air-floatation radial bearing 113 and the first stub shaft 116, and then flows into the air-floatation radial bearing 113 on the other side through the stator-rotor air gap, and the cooling channel cools the air-floatation radial bearing 113 and the surface of the rotor 111 at the same time, the temperature rise of the bearing is reduced, the service life of the surface coating is prolonged, meanwhile, the cooling air flow enables the air in the motor to flow, and the bearing performance of the air bearing is effectively improved.

Referring to fig. 1, the end of the second short shaft 115 is connected to a second impeller 102, in which case the second impeller 102 is a first-stage impeller, the first impeller 104 is a second-stage impeller, and in which case the corresponding air compressor is a two-stage air compressor.

The housing 109 is configured with a cooling water channel 119, which is capable of performing heat exchange cooling on the cooling gas in the first cooling gas channel 202, specifically, the cooling gas may be provided by an external gas source, and in the case of no external gas source, a part of the compressed gas may be branched off from the first or second stage exhaust side of the air compressor to enter the cooling flow channel.

According to the utility model discloses an embodiment still provides an air compressor, including foretell air compressor cooling structure.

It is readily understood by a person skilled in the art that the advantageous ways described above can be freely combined, superimposed without conflict.

The above description is only exemplary of the present invention and should not be construed as limiting the present invention, and any modifications, equivalents and improvements made within the spirit and principles of the present invention are intended to be included within the scope of the present invention. The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims

1. The air compressor cooling structure is characterized by comprising a machine shell (109), wherein a motor rotor (111) is arranged in the machine shell (109), the motor rotor (111) comprises a second short shaft (115) and a first short shaft (116) which are arranged along the axial direction of the motor rotor (111) at intervals, a thrust disc (114) corresponding to an air floatation axial bearing (112) is arranged on the second short shaft (115), a first impeller (104) is connected to the shaft end of the first short shaft (116), a first cooling air channel (202) is constructed on the machine shell (109), a through flow channel (201) is constructed in the first short shaft (116), and cooling air flow outside the machine shell (109) is discharged outside the machine shell (109) after passing through the first cooling air channel (202) and the through flow channel (201).

2. The air compressor cooling structure according to claim 1, wherein the first stub shaft (116) is rotatably supported on a first end cover (108), the first end cover (108) is disposed at a first end of the casing (109), a second cooling air duct (2021) is configured on the first end cover (108), and the cooling air flow in the first cooling air duct (202) can enter the through-flow passage (201) through the second cooling air duct (2021).

3. The air compressor cooling structure according to claim 2, wherein a first diffuser (106) is connected to a side of the first end cover (108) facing the first impeller (104), a third cooling air passage (2022) is configured on the first diffuser (106), and the cooling air flow in the second cooling air passage (2021) can enter the through-flow passage (201) through the third cooling air passage (2022).

4. The air compressor cooling structure according to claim 3, wherein the first stub shaft (116) has a shoulder annulus facing a side of the first impeller (104), the first diffuser (106) has an axial boss (1061) extending toward the shoulder annulus, an inlet of the through-flow passage (201) is on the shoulder annulus, an outlet of the third cooling air passage (2022) is on the axial boss (1061), and an outlet of the third cooling air passage (2022) and an inlet of the through-flow passage (201) are alignable in an axial direction of the motor rotor (111).

5. The air compressor cooling structure of claim 4, wherein the first diffuser (106) is made of an abrasion resistant material.

6. The air compressor cooling structure of claim 4, wherein an axial clearance formed between the axial boss (1061) and the shoulder ring land has a clearance amount δ 1, and a tip clearance of the first impeller (104) is δ, δ 1 < δ.

7. The air compressor cooling structure of claim 6, wherein δ - δ 1 > 0.15 mm.

8. The air compressor cooling structure according to claim 1, wherein a magnetic steel (117) is sandwiched between the second stub shaft (115) and the first stub shaft (116), and the through flow passage (201) has a passage section disposed adjacent to the magnetic steel (117); and/or the circulation path of the through flow channel (201) is U-shaped or V-shaped; and/or the through flow channel (201) is provided with a plurality of strips.

9. The air compressor cooling structure according to claim 1, wherein a lubricating coating is provided on an area of the outer circumferential wall of the first stub shaft (116) corresponding to the air bearing (113); and/or a second impeller (102) is connected to the end of the second short shaft (115); and/or a cooling water channel (119) is formed on the machine shell (109).

10. An air compressor characterized by comprising the air compressor cooling structure of any one of claims 1 to 9.