CN215633844U - Centrifugal air compressor - Google Patents

Abstract

A centrifugal air compressor including a rotary shaft partially accommodated in an end cover and a motor housing and having a body and a flying disc extending in a radial direction; an impeller mounted to the shaft, partially enclosed by the housing and the back cover; thrust bearings respectively arranged at two sides of the flying disc, and a left gap and a right gap are respectively formed between the flying disc and the thrust bearings; a radial bearing disposed on the rotating shaft, a rotating shaft gap being provided between the radial bearing and the rotating shaft; a cooling medium inlet; a first flow passage communicating with the cooling medium inlet and introducing the medium into a left gap in the center of the flying disc, the cooling medium passing through the left gap and flowing from the center of the flying disc to the edge of the flying disc; and a second flow passage communicating with the cooling medium inlet and introducing the medium into a right gap in the center of the flying disc, through which the cooling medium flows from the center of the flying disc to the edge of the flying disc. By adopting the structure, the cooling medium enters from the center of the flying disc and flows to the outer edge, so that the cooling efficiency of the flying disc and the thrust bearing is improved, and the failure risk of the thrust bearing is reduced.

Description

Centrifugal air compressor

Technical Field

The present application relates to air compressors and, more particularly, to centrifugal air compressors having cooling paths for directly cooling flying discs and thrust bearings.

Background

The electric air compressor is widely applied in various industries, in particular to a centrifugal air compressor, which is not only suitable for occasions with low pressure, medium pressure and large flow, but also greatly expands the application range along with the improvement of oil seal technology, so that the electric air compressor can replace a reciprocating compressor in many occasions and greatly expands the application range. In a conventional centrifugal air compressor, cooling of a rotor is performed by a flow of cooling air, and in the centrifugal air compressor, thrust bearings are provided on both sides of a flying disc of a rotating shaft to support the rotating shaft for normal rotation, and in order to cool the rotor, cooling air is generally introduced between the thrust bearings and the flying disc of the rotating shaft, thereby removing heat generated at the thrust bearings and the flying disc. However, the cooling in the conventional centrifugal air compression is often not efficient enough, especially at the position close to the outer edge of the flying disc, on the one hand, the centrifugal force and high speed of the flying disc rotation will throw high-temperature air to the position to form a high-temperature region, on the other hand, an air film will be formed between the flying disc of the rotating shaft and the foil thrust bearing, and by means of the centrifugal force generated when the rotating shaft rotates, the air film will form a high-pressure region at the periphery of the flying disc, and a low-pressure region at the center of the flying disc, therefore, the cooling air is difficult to enter into the air film to reduce the temperature of the air film, so that the air temperature between the thrust bearing and the flying disc is very high, the coating of the thrust bearing will melt, and the whole compressor will fail.

Accordingly, there is a need for an improvement in the cooling structure of the existing centrifugal air compressor to provide a centrifugal air compressor capable of reducing the temperature around the thrust bearing to prevent the coating of the thrust bearing from melting.

SUMMERY OF THE UTILITY MODEL

It is an object of the present application to provide a centrifugal air compressor with an improved cooling medium flow path for efficient cooling between the flying disc and the thrust bearing.

To this end, the present application provides a centrifugal air compressor comprising: a shaft coupled to the power output source to provide a rotational force, the shaft being partially received in the end cap and the motor housing, the shaft having a body and a flying disc extending radially from the body; an impeller mounted to the shaft, the impeller partially enclosed by the shroud and the back cover; thrust bearings respectively arranged at two axial sides of the flying disc, and a left gap and a right gap are respectively formed between the two sides of the flying disc and the thrust bearings; and a radial bearing provided on the rotating shaft with a rotating shaft gap therebetween, wherein the centrifugal air compressor further comprises: a cooling medium inlet; a first flow passage communicating with the cooling medium inlet and for introducing the cooling medium into the left gap at the center of the flying disc, the cooling medium flowing from the center of the flying disc to the edge of the flying disc through the left gap; and a second flow passage communicating with the cooling medium inlet and for introducing the cooling medium into the right gap at a center position of the flying disc, the cooling medium flowing from the center of the flying disc to an edge of the flying disc through the right gap.

Optionally, the centrifugal air compressor further has a first bearing fixing member and a second bearing fixing member for fixing the thrust bearing, the first flow passage is formed between the back cover plate and the first bearing fixing member, the second flow passage is formed between the motor housing and the stator housing, and the cooling medium passes through the second flow passage and then passes through the rotating shaft gap into the right gap between the flying disc and the thrust bearing.

Wherein the cooling medium inlet is disposed in the motor housing and is in fluid communication with the first and second flow passages through a groove disposed in the back cover plate.

Alternatively, the thrust bearings are fixed in bearing receiving portions of the back cover plate and the end cover, respectively, and the first flow passage is formed in the back cover plate and the second flow passage is formed by a gap between the end cover and the stator housing.

Alternatively, the thrust bearings are fixed in bearing receiving portions of the rear cover plate and the end cover, respectively, the first flow passage is formed in the rear cover plate, the second flow passage is formed in the end cover, and the second flow passage leads from the cooling medium inlet directly to the center of the flying disc.

Wherein, the end cover is connected with the stator shell in a sealing way.

Optionally, the cooling medium inlet is formed in the end cover, the end cover further having a first angled passage formed therein leading from the cooling medium inlet to the rear cover plate.

Or, a second inclined channel is formed in the rear cover plate and is respectively communicated with the first inclined channel and the first flow channel in a fluid mode.

Alternatively, the cooling medium inlet is formed in the motor case so as to be integrally inclined during the manufacturing process of the motor case.

Alternatively, the cooling medium inlet is formed in the end cap in a direction perpendicular to the rotation axis and is connected to the pipe joint

The centrifugal air compressor with the cooling medium flow path is adopted, the flow path of the cooling medium is set to enable the cooling medium to firstly reach the center of the flying disc at two sides of the flying disc respectively, then the cooling medium flows through the gap between the flying disc and the thrust bearing from the center of the flying disc to reach the edge of the flying disc, the defect that the edge forms a high-pressure area due to the rotating centrifugal force of the rotating shaft at the edge of the flying disc and then prevents the cooling medium from entering is overcome, more cooling medium can easily penetrate through an air film between the thrust bearing and the flying disc, the surface temperature of the thrust air bearing can be reduced, the bearing coating is prevented from melting, and the service life of the whole centrifugal air compressor is prolonged.

Drawings

The foregoing and other aspects of the present application will be more fully understood from the following detailed description, taken together with the following drawings. It is noted that the drawings may not be to scale for clarity of illustration and will not detract from the understanding of the present application. In the drawings:

FIG. 1 is a centrifugal air compressor according to a first embodiment of the present application;

FIG. 2 is a centrifugal air compressor according to a second embodiment of the present application; and

FIG. 3 is a centrifugal air compressor according to a third embodiment of the present application.

Detailed Description

In the drawings of the present application, features that are structurally identical or functionally similar are denoted by the same reference numerals, which are not drawn to scale but are exaggerated for clarity.

FIG. 1 is a centrifugal air compressor according to a first embodiment of the present application. The centrifugal air compressor includes an impeller 1 and a rotating shaft 2 connected to the impeller 1 to transmit a rotational motion to the impeller 1. The impeller 1 is partially enclosed by a back cover plate 3 and a casing 30, and the rotating shaft 2 is partially accommodated in a motor housing 4 fitted with the casing 30 and has a body portion and a flying disc 5 extending perpendicularly therefrom. The centrifugal air compressor of the present embodiment also has an end cover 31 fitted between the back cover plate 3, the cover case 30 and the motor case 4. The flying disc 5 is fitted with thrust air bearings 7 and 8 on both axial sides, respectively, for which purpose first and second bearing fixtures 9 and 32 are provided on the axial outer sides of the thrust air bearings 7 and 8, respectively, and a cooling ring 6 is provided between the first and second bearing fixtures 9 and 32 and on the radial outer side of the flying disc 5, the first bearing fixture 9, the cooling ring 6, and the second bearing fixture 12 being fixed to the motor housing 4 by fasteners. On the outside of the second bearing fixing 12, there is a radial bearing 10 between the main part of the shaft 2 and the motor housing 4, with a shaft gap 16 between the radial bearing 10 and the main part of the shaft 2.

When assembled, the back cover plate 3 and the first bearing fixing member 9 have a gap therebetween to form a first flow passage 13 for a cooling medium to flow, the end cover 31 is a plate member having a recess 12, a cooling medium inlet 11 for the cooling medium to enter is formed in the motor housing 4, and the recess 12 is in fluid communication with the cooling medium inlet 11 after the end cover 31 is fitted to the motor housing 4.

Between the outer peripheries of the first bearing fixing member 9, the cooling ring 6 and the second bearing fixing member 12 and the inner periphery of the end cover 31, a space is also formed so that the groove 12 is in fluid communication with the first flow passage 13.

A first flow passage 15 is formed in the motor housing 4 so that the recess 12 and the rotation shaft gap 16 are in fluid communication to guide a cooling medium into the rotation shaft gap 16, and a second flow passage 15 is formed by a gap between the motor housing 4 and the stator housing.

The process of cooling the thrust bearing and the flying disc 5 in the centrifugal air compressor of this embodiment will be described in detail below. By means of the cooling ring 6 and the two bearing holders 9 and 32, a left gap 14 and a right gap 17 are provided between the flying disc 5 and the two thrust bearings, respectively, and during operation, a cooling medium, such as cooling air, enters the groove 12 through the cooling medium inlet 11, and is then divided into two paths, one path flows to a position between the center of the first bearing holder 9 and the rotating shaft 2 through the first flow passage 13, then flows through the left gap 14 from the center of the flying disc 5 to the outer edge of the flying disc 5, and the other path flows into the rotating shaft gap 16 through the second flow passage 15, flows along the rotating shaft gap 16 to the center of the flying disc 5, and then flows through the right gap 17 from the center of the flying disc 5 to the outer edge of the flying disc 5. Such a flow allows the cooling medium to rapidly and smoothly enter the left and right clearances 14, 17, thereby enabling efficient cooling of the flying disc 5 and the thrust bearings 7, 8. The flow path of the cooling medium is shown by the arrows in fig. 1.

Fig. 2 shows a partial cross-sectional view of a centrifugal air compressor of a second embodiment of the present application, the same structures as those in fig. 1 being denoted by the same reference numerals, and the second embodiment differs from the first embodiment in the arrangement of the back cover plate and the end cover, and the respective flow passages, and the description will not be repeated for the same points, and only the differences between the two embodiments will be described.

As shown in fig. 2, in the second embodiment, the first and second bearing fixtures 9 and 32 and the cooling ring 6 in the first embodiment are omitted, and the configurations of the rear cover plate 3 and the end cover 31 are changed. In the second embodiment, the cover 30 is not fitted to the motor housing 4, but fitted to the end cap 31, the end cap 31 is fitted to the motor housing 4, and the rear cover 3 is disposed between the cover 30 and the end cap 31.

A flying disc accommodating portion 33 for accommodating the flying disc 5 is formed in the rear cover plate 3, a recessed thrust bearing accommodating portion 34 is provided on an inner surface of the flying disc accommodating portion 33, the thrust bearing 7 is accommodated in the thrust bearing accommodating portion 34, a recessed thrust bearing accommodating portion 35 is also provided on a surface of the end cover 31 for accommodating the thrust bearing 8, and after assembly, clearances, i.e., the left clearance 14 and the right clearance 17 as in the first embodiment, are provided between the flying disc 5 and the thrust bearings 7, 8, respectively.

In fig. 2, the cooling medium inlet 11 is modified to be disposed in the end cover 31 and introduced through various joints known in the art. In the end cover 31, a first inclined passage 21 leading from the cooling medium inlet 11 to the rear cover plate 3 is provided, in the rear cover plate 3, a second inclined passage 22 communicating with the first inclined passage 21 is provided, and further, in the rear cover plate 3, a first flow passage 13 communicating with the second inclined passage 22 is provided, the first flow passage 13 leading to the center of the flying disc 5. In the second embodiment, the second flow passage 15 is formed by the gap between the end cover 31 and the stator housing. In this embodiment, there is also a radial bearing 10 between the main part of the shaft 2 and the motor housing 4, outside the flying disc 5, with a shaft gap 16 between the radial bearing 10 and the main part of the shaft 2.

Although the first inclined channel 21 and the second inclined channel 22 shown in fig. 2 are inclined with respect to the horizontal direction, they may be provided as horizontal channels or curved channels depending on the actual size and structure of the rear cover plate 3 and the end cover 31.

Similarly, in the centrifugal air compressor of the second embodiment, the flying disc 5 and the two thrust bearings 7 and 8 also have the left gap 14 and the right gap 17 therebetween, and during operation, a cooling medium, such as cooling air, enters through the cooling medium inlet 11, and is then divided into two paths, one path enters into the first flow passage 13 via the first inclined passage 21 and the second inclined passage 22, and flows to the center of the flying disc 5 through the first flow passage 13, and then flows through the left gap 14 from the center of the flying disc 5 to the outer edge of the flying disc 5, and the other path flows into the shaft gap 16 through the second flow passage 15, follows the shaft gap 16 to the center of the flying disc 5, and then flows through the right gap 17 from the center of the flying disc 5 to the outer edge of the flying disc 5. Such a flow also enables efficient cooling of the flying disc 5 and the thrust bearings 7, 8. The flow path of the cooling medium is shown by the arrows in fig. 2.

Fig. 3 shows a centrifugal air compressor according to a third embodiment of the present application, which is substantially identical to the second embodiment except that the second flow passages 15 in the second embodiment are replaced with third flow passages 25. Description is not repeated for the same structure, and only the difference from the second embodiment is described.

In fig. 3, the end cover 31 is no longer provided with a gap between it and the stator housing, which allows the cooling medium to flow, but is connected in a gas-tight manner. Instead, in end cover 31, third flow passage 25 is provided in a direction from cooling medium inlet 11 toward the center of flying disc 5, so that the cooling medium can be directly introduced through third flow passage 25 to the center of the flying disc on the right side of flying disc 5.

Thus, in the centrifugal air compressor of the third embodiment, the flying disc 5 and the two thrust bearings 7, 8 also have the left gap 14 and the right gap 17 therebetween, and during operation, a cooling medium, such as cooling air, enters through the cooling medium inlet 11, and is then split into two paths, one path entering into the first flow path 13 via the first inclined path 21 and the second inclined path 22, and flowing through the first flow path 13 to the center position of the flying disc 5, and then flowing through the left gap 14 from the center of the flying disc 5 to the outer edge of the flying disc 5, and the other path directly reaching the center of the flying disc 5 through the third flow path 25, and then flowing through the right gap 17 from the center of the flying disc 5 to the outer edge of the flying disc 5. Such a flow also enables efficient cooling of the flying disc 5 and the thrust bearings 7, 8. The flow path of the cooling medium is shown by the arrows in fig. 3. In this embodiment, very little cooling medium is allowed to enter the small gap first and then the right thrust bearing 8, but directly at the thrust bearing 8, further increasing the cooling efficiency.

Thus, in the centrifugal air compressor of the embodiments of the present application, by setting the flow paths of the cooling medium so that the cooling medium first reaches the center of flying disc 5 on both sides of flying disc 5, and then flows from the center of flying disc 5 through gaps 14, 17 between flying disc 5 and thrust bearings 7, 8 to the edge of flying disc 5, respectively, the defect that the edge forms a high-pressure zone due to the rotating centrifugal force of the rotating shaft at the edge of flying disc 5 and thereby hinders the entry of the cooling medium is overcome, so that more cooling medium can easily pass through the air film between the thrust bearing and flying disc, and the surface temperature of the thrust air bearing can be reduced, and the bearing coating is prevented from melting.

Particularly in the third embodiment, by causing the cooling medium to directly reach the center of the flying disc and directly enter the thrust bearing in the cooling medium flow path on the right side of the flying disc, the flow of the cooling medium is also increased, the temperature rise when the cooling medium passes through a small gap, is heated by the radial bearing and the rotating shaft, and then enters the thrust bearing is avoided, and the efficiency of cooling the thrust bearing is improved.

Although specific embodiments of the present application have been described herein in detail, they have been presented for purposes of illustration only and are not to be construed as limiting the scope of the application. Various substitutions, alterations, and modifications may be conceived without departing from the spirit and scope of the present application.

Claims (10)

1. A centrifugal air compressor, comprising:

a shaft coupled to the power output source to provide a rotational force, the shaft being partially received in the end cap and the motor housing, the shaft having a body and a flying disc extending radially from the body;

an impeller mounted to the shaft, the impeller partially enclosed by the shroud and the back cover;

thrust bearings respectively arranged at two axial sides of the flying disc, and a left gap and a right gap are respectively formed between the two sides of the flying disc and the thrust bearings; and

a radial bearing arranged on the rotating shaft, a rotating shaft gap is arranged between the radial bearing and the rotating shaft,

wherein the centrifugal air compressor further comprises:

a cooling medium inlet;

a first flow passage communicating with the cooling medium inlet and for introducing the cooling medium into the left gap at the center of the flying disc, the cooling medium flowing from the center of the flying disc to the edge of the flying disc through the left gap;

and a second flow passage communicating with the cooling medium inlet and for introducing the cooling medium into the right gap at a center position of the flying disc, the cooling medium flowing from the center of the flying disc to an edge of the flying disc through the right gap.

2. The centrifugal air compressor according to claim 1, further comprising a first bearing fixing member and a second bearing fixing member for fixing the thrust bearing, wherein the first flow passage is formed between the back cover plate and the first bearing fixing member, the second flow passage is formed between the motor housing and the stator housing, and the cooling medium passes through the rotation shaft gap after passing through the second flow passage into a right gap between the flying disc and the thrust bearing.

3. The centrifugal air compressor as claimed in claim 2, wherein the cooling medium inlet is disposed in the motor housing and is in fluid communication with the first and second flow passages through a groove disposed in the back cover plate.

4. The centrifugal air compressor according to claim 1, wherein the thrust bearings are fixed in bearing receiving portions of the back cover plate and the end cover, respectively, and the first flow passage is formed in the back cover plate, and the second flow passage is formed by a gap between the end cover and a stator housing.

5. The centrifugal air compressor as claimed in claim 1, wherein the thrust bearings are fixed in bearing receiving portions of the back cover plate and the end cover, respectively, the first flow passage is formed in the back cover plate, the second flow passage is formed in the end cover, and the second flow passage leads from the cooling medium inlet directly to a center of the flying disc.

6. The centrifugal air compressor as claimed in claim 5, wherein the end cover is sealingly connected to the stator housing.

7. A centrifugal air compressor according to claim 4 or 5 wherein the cooling medium inlet is formed in the end cover, the end cover also having formed therein a first inclined passage leading from the cooling medium inlet to the back cover plate.

8. The centrifugal air compressor as claimed in claim 7, wherein the back cover plate further has a second inclined passage formed therein, the second inclined passage being in fluid communication with the first inclined passage and the first flow passage, respectively.

9. The centrifugal air compressor as claimed in claim 1, wherein the cooling medium inlet is integrally formed in the motor housing during manufacture of the motor housing.

10. The centrifugal air compressor according to claim 4 or 5, wherein the cooling medium inlet is formed in the end cover in a direction perpendicular to the rotation shaft and is connected to a pipe joint.

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