CN217029398U - Centrifugal impeller and centrifugal compressor with same - Google Patents

Abstract

The utility model provides a centrifugal impeller and a centrifugal compressor with the same, wherein the centrifugal impeller comprises a first wheel disc, wherein a plurality of first blades arrayed along the circumferential direction of the first wheel disc are convexly formed on one side surface of the first wheel disc; the second wheel disc is detachably connected with the first wheel disc, a plurality of second blades are formed on the surface of one side, facing the first wheel disc, of the second wheel disc in a protruding mode, and the plurality of first blades are in one-to-one butt joint with the plurality of second blades to form blades of the centrifugal impeller; positioning columns are formed on at least part of the first blades and are inserted into positioning holes formed in the corresponding second blades; and/or at least part of the second blades are provided with positioning columns which are inserted into the corresponding positioning holes formed in the first blades so as to restrain and position the first wheel disc and the second wheel disc. The first wheel disc and the second wheel disc in the centrifugal impeller are split, so that the first blade and the second blade can be conveniently subjected to surface finish processing, the practicability is high, and the popularization is easy.

Description

Centrifugal impeller and centrifugal compressor with same

Technical Field

The utility model belongs to the technical field of compressors, and particularly relates to a centrifugal impeller and a centrifugal compressor with the same.

Background

The centrifugal compressor has the remarkable advantages of energy conservation, high efficiency, stable operation and long service life. However, in the refrigeration field, the centrifugal compressor is suitable for large-flow and low-pressure-ratio working occasions, and the efficient low-flow and high-pressure-ratio operation is difficult to realize. Therefore, the centrifugal compressor is applied to a large-cooling-capacity water chilling unit. The small and medium-sized refrigeration systems are more commonly used with screw compressors, scroll compressors (such as small central air conditioners including multi-split air conditioners) and rolling rotor compressors. These types of compressors, however, operate far less efficiently than centrifugal compressors. Most of these types of compressors are lubricated with lubricating oil. The problems that the lubricating oil is accumulated in the heat exchanger, the oil is disadvantageously returned to the compressor, the lubrication of related compression parts is poor, the heat exchange resistance of the heat exchanger is increased and the like are easily caused.

Moreover, the impeller processing of small-cooling capacity high-speed centrifuges becomes an industrial problem, especially for micro-miniature centrifugal impellers. Although casting can be integrally formed, the requirements of small impeller surface roughness and the like are high, the casting process is difficult to directly meet the precision requirement, and the small impeller is difficult to precisely treat the inside of the small impeller by other measures due to the small size.

Therefore, how to solve various problems caused by the miniaturization of the centrifugal compressor can make the centrifugal compressor applied to small and medium-sized refrigeration systems to replace screw compressors, scroll compressors and even rolling rotor compressors, so that the energy efficiency of the refrigeration systems is higher, and the refrigeration industry is influenced profoundly.

SUMMERY OF THE UTILITY MODEL

The object of the present invention is to overcome at least one of the drawbacks of the prior art and to provide a centrifugal impeller that facilitates the finishing of the surface of the blades.

It is a further object of the present invention to improve the accuracy of the fit of the first and second wheels.

Another object of the present invention is to provide a centrifugal compressor having the above centrifugal impeller.

In one aspect, the present invention provides a centrifugal impeller for a centrifugal compressor comprising:

a first wheel disc, wherein a plurality of first blades arranged along the circumferential direction of the first wheel disc are convexly formed on one side surface of the first wheel disc;

the second wheel disc is detachably connected with the first wheel disc, a plurality of second blades are formed on the surface of one side, facing the first wheel disc, of the second wheel disc in a protruding mode, and the plurality of first blades are in one-to-one butt joint with the plurality of second blades to form blades of the centrifugal impeller;

positioning columns are formed on at least part of the first blades and are inserted into positioning holes formed in the corresponding second blades; and/or

And at least part of the second blades are provided with positioning columns which are inserted into the corresponding positioning holes formed in the first blades so as to constrain and position the first wheel disc and the second wheel disc.

Optionally, at least part of the first blades and the corresponding second blades are provided with mounting holes, so that the first wheel disc and the second wheel disc are fixed to each other by means of screwing or riveting.

Optionally, each mounting hole penetrates through the positioning column or the positioning hole.

Optionally, the mounting hole is not arranged in line with the axis of the positioning post or the positioning hole.

Optionally, each first blade is formed with a positioning column, and each second blade is formed with a positioning hole; or each second blade is provided with a positioning column, and each first blade is provided with a positioning hole.

Optionally, the positioning column and the positioning hole are circular or elliptical.

Optionally, the junction of the first blade and the rest of the first disk is formed with a first fillet; the junction of the second blade and the remainder of the second disk is formed with a second fillet.

Optionally, the radius of each first fillet is between 1/8 and 1 of the first vane height; and each second fillet has a radius between 1/8 and 1 of the second lobe height.

In another aspect, the utility model also provides a centrifugal compressor comprising a centrifugal impeller as described in any one of the above.

Optionally, the centrifugal compressor further comprises: a housing; the motor is arranged in the shell; and at least one compression unit, each compression unit comprises a volute and a centrifugal impeller, the volute is arranged in the machine shell, the centrifugal impeller is arranged in the volute, and the centrifugal impeller is configured to rotate under the driving of a motor so as to compress the air flow entering the volute and discharge the air flow through an outlet of the volute.

In the centrifugal impeller, the first blades are arranged along the circumferential direction of the first wheel disc on one side surface of the first wheel disc, the second wheel disc is detachably connected with the first wheel disc, the second blades are arranged on one side surface of the second wheel disc, which faces the first wheel disc, and the first blades and the second blades are in one-to-one butt joint to form the blades of the centrifugal impeller. First rim plate and second rim plate adopt split type, after first rim plate and second rim plate shaping separately, have shortened centrifugal impeller's the whole height of blade, are convenient for carry out finish machining to the surface of first blade and second blade for blade surface precision is higher, and is more smooth, promotes the performance of impeller. In addition, the mode can also enable a cutter and the like to extend into the space between the adjacent first blades or the adjacent second blades, so that round corners can be conveniently machined on the first blades and the second blades, smooth transition is realized, and corner vortexes are prevented from being generated when gas circulates in the airflow channel.

In the centrifugal impeller, the positioning columns and the positioning holes are arranged on at least part of the first blade and the second blade, so that the positioning columns are inserted into the positioning holes, the first blade and the second blade are accurately positioned, the first blade and the second blade are more accurately connected, and the phenomenon that small steps are formed by dislocation, the smoothness of a flow channel in the centrifugal impeller is influenced, the flow field is disturbed, the pneumatic performance is low, and the loss is increased is avoided.

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

Drawings

Some specific embodiments of the utility model will be described in detail hereinafter by way of example and not by way of limitation with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily to scale. In the drawings:

FIG. 1 is a schematic structural view of a centrifugal impeller according to one embodiment of the present invention;

FIG. 2 is an exploded schematic view of the centrifugal impeller of FIG. 1;

FIG. 3 is another angular schematic view of the second wheel disc of FIG. 2;

FIG. 4 is a schematic view of the first and second fillets of a centrifugal impeller;

fig. 5 is a schematic view of the overall structure of a centrifugal compressor according to an embodiment of the present invention;

fig. 6 is a schematic sectional view of the centrifugal compressor shown in fig. 5 taken along the axial direction of the centrifugal impeller;

FIG. 7 is an enlarged view at A of FIG. 6;

FIG. 8 is a schematic diagram of the structure of one of the compression units of FIG. 1;

FIG. 9 is another perspective view of the compression unit of FIG. 8;

fig. 10 is an exploded schematic view of the compression unit shown in fig. 8.

Detailed Description

A centrifugal impeller and a centrifugal compressor having the same according to an embodiment of the present invention will be described with reference to fig. 1 to 10. Where the orientations or positional relationships indicated by the terms "front," "back," "upper," "lower," "top," "bottom," "inner," "outer," "lateral," and the like are based on the orientations or positional relationships shown in the drawings, the description is for convenience only and to simplify the description, and no indication or suggestion is made that the device or element so indicated must have a particular orientation, be constructed and operated in a particular orientation, and is therefore not to be construed as limiting the utility model.

FIG. 1 is a schematic structural view of a centrifugal impeller according to one embodiment of the present invention; FIG. 2 is an exploded schematic view of the centrifugal impeller of FIG. 1; fig. 3 is another angular schematic view of the second wheel disc of fig. 2.

As shown in fig. 1 to 3, an embodiment of the present invention provides a centrifugal impeller 200 for a centrifugal compressor. Centrifugal impeller 200 may generally include a first disk 210 and a second disk 220. Wherein, a plurality of first blades 212 arranged along a circumferential direction of the first disk 210 are protrudingly formed on one side surface of the first disk 210. The second disk 220 is detachably connected to the first disk 210, and a plurality of second blades 222 are formed by protruding the second disk 220 toward one side surface of the first disk 210, and the plurality of first blades 212 are in one-to-one butt joint with the plurality of second blades 222 to constitute blades of the centrifugal impeller 200. That is, the second blades 222 are the same in number as the first blades 212 and are positioned in a one-to-one correspondence. An airflow channel of the centrifugal impeller 200 is formed between each two adjacent blades.

Specifically, the first and second discs 210, 220 are generally circular in shape and are coaxially disposed. The first disk 210 has an inlet 201 formed at the center thereof for sucking a low-pressure refrigerant gas flow, and an outlet 202 formed at the circumferential direction thereof after the first disk 210 is connected to the second disk 220 for discharging a high-pressure refrigerant gas flow compressed by the blades (formed by the connection of the first blade 212 and the second blade 222).

Moreover, at least a part (meaning a part or all) of the first blades 212 are formed with positioning posts 214 which are inserted into corresponding positioning holes 224 formed in the second blades 222; and/or

At least a portion of the second blades 222 is formed with positioning posts 214 that are inserted into corresponding positioning holes 224 formed in the first blades 212 to constrain and position the first and second discs 210 and 220.

For example, one or more first blades 212 may be formed with positioning posts 214, and each second blade 222 at a corresponding position may be formed with positioning holes 224. Alternatively, one or more first blades 212 are formed with positioning holes 224, and each second blade 222 at a corresponding position is formed with a positioning post 214. Alternatively, a positioning post 214 is formed on a part of the first blade 212, a positioning hole 224 is formed on another part of the first blade 212, and the positioning hole 224 and the positioning post 214 are correspondingly disposed on the corresponding second blade 222.

The positioning holes 224 and the positioning posts 214 are identical in shape to realize positioning. The positioning holes 224 and the positioning posts 214 may be circular or oval, preferably circular.

For the solution of providing multiple sets of positioning holes 224 and positioning posts 214, the shapes of the multiple sets of positioning holes 224 and positioning posts 214 may not be completely the same or different. For example, part of the positioning holes and the positioning columns are circular, and the rest of the positioning holes and the positioning columns are polygonal.

At present, the processing of the impeller of a small-cooling capacity high-speed centrifugal machine becomes an industrial problem, particularly for a microminiature centrifugal impeller. Although casting can be integrally formed, the requirements of small impeller surface roughness and the like are high, the casting process is difficult to directly meet the precision requirement, and the small impeller is difficult to precisely treat the inside of the small impeller by other measures due to the small size.

In order to overcome the defects in the prior art, the centrifugal impeller 200 in the embodiment adopts the mode that the blades are split and arranged on the first wheel disc 210 and the second wheel disc 220, and the first wheel disc 210 and the second wheel disc 220 adopt the split mode, so that the integral height of the blades of the centrifugal impeller 200 is shortened after the first wheel disc 210 and the second wheel disc 220 are respectively molded, the fine machining treatment is conveniently carried out on the surfaces of the first blades 212 and the second blades 222, and the surface precision of the blades is higher and smoother. In addition, in this way, the cutter can conveniently extend into the space between the adjacent first blades 212 or the adjacent second blades 222, so that fillets 240 can be conveniently machined on the first blades 212 and the second blades 222, the airflow channel of the centrifugal impeller 200 is further made smoother, smooth transition is realized, and angular vortexes are avoided when air circulates in the airflow channel 2102.

In addition, in the embodiment of the present invention, at least a portion of the first blade 212 and the second blade 222 are provided with the positioning column 214 and the positioning hole 224, and the positioning column 214 is inserted into the positioning hole 224, so as to achieve accurate positioning of the first blade 212 and the second blade 222, and achieve more accurate engagement between the first blade 212 and the second blade 222, thereby avoiding the occurrence of small steps formed by dislocation, which affects the smoothness of a flow channel in an impeller, and causes turbulence of a flow field, which results in low aerodynamic performance and increased loss.

For example, as shown in fig. 1 to fig. 4, each first blade 212 may be formed with a positioning post 214, and each second blade 222 may be formed with a positioning hole 224, so that each first blade 212 and the corresponding second blade 222 are precisely positioned. In order to make the centrifugal impeller 200 more balanced overall, each positioning post 214 on the first disk 210 may be located on a circumference concentric with the first disk 210. With the positioning holes 224 of the second wheel 220 located on a circumference concentric with the second wheel 220.

In some alternative embodiments, not illustrated in the figures, each second vane may also be formed with a positioning post and each first vane may be formed with a positioning hole.

In some embodiments of the present invention, at least a portion of the first blades 212 and the corresponding second blades 222 are each formed with mounting holes 216 and 226 to secure the first disk 210 and the second disk 220 to each other by screwing or riveting.

Further, each mounting hole 216 and 226 may be positioned through either locating post 214 or locating hole 224. For example, for the embodiment shown in fig. 1-4, mounting holes 216, 226 of first blade 212 are each passed through locating post 214, and mounting hole 216 and mounting hole 226 of second blade 222 are passed through locating hole 224. As such, the amount of opening of the second disk 220 may be reduced, and the structural strength of the second disk 220, particularly at the second vane 222, may be improved.

Referring to fig. 1 to 3, in some embodiments, the mounting hole 226 formed on the second blade 222 may be provided with a thread, and the screw 230 is screwed on the mounting hole 226 of the second blade 222 after passing through the mounting hole 216 of the first blade 212. Of course, in some embodiments not shown in the drawings, each of the mounting holes 216 and 226 may not be threaded, and the first wheel 210 and the second wheel 220 may be fastened together by rivets.

In some embodiments, each of the mounting holes 216 and 226 may be arranged non-collinear with the axis of the positioning post 214 or the positioning hole 224, which not only reduces the difficulty of machining, but also improves the positioning accuracy of the first wheel disc 210 and the second wheel disc 220.

Fig. 4 is a schematic structural view of a first fillet and a second fillet in the centrifugal impeller. As shown in FIG. 4, in some embodiments, the junction of the first blade 212 and the remainder of the first disk 210 is formed with a first fillet 242, and the junction of the second blade 222 and the remainder of the second disk 220 is formed with a second fillet 244. Through setting up first fillet 242 and second fillet 244, not only can improve the intensity at first blade 212 and second blade 222 root, alleviate this local stress concentration, can make moreover every airflow channel more smooth, eliminated the angular vortex phenomenon of air current, guaranteed the homogeneity in flow field.

Referring to fig. 4, H1 indicates the height of the first blade 212, H2 indicates the height of the second blade 222, R1 indicates the radius of the first fillet 242, and R2 indicates the radius of the second fillet 244 in fig. 4; further, the radius R1 of the first fillet 242 may also be configured to be between 1/8 and 1 of the height H1 of the first blade 212, and the radius R2 of the second fillet 244 may also be configured to be between 1/8 and 1 of the height H2 of the second blade 222, for example, 1/8, 1/5, or 1, and so on. Through a plurality of experiments, the inventor finds that a better airflow field can be obtained on the premise of not influencing the area of the airflow channel 2102 by the limitation, so that the airflow compression effect is further improved.

The present invention also provides a centrifugal compressor comprising a centrifugal impeller 200 as described in any of the above embodiments.

FIG. 5 is a schematic diagram of the overall structure of a centrifugal compressor according to an embodiment of the present invention; fig. 6 is a schematic sectional view of the centrifugal compressor shown in fig. 5, taken along the axial direction of the centrifugal impeller 200; fig. 7 is an enlarged view of fig. 6 at a.

In some embodiments, as shown in fig. 5-7, in some embodiments, a centrifugal compressor includes a casing 10, a motor 40, and at least one compression unit 20, 30. The cabinet 10 defines an accommodating space, and the motor 40 is installed in the cabinet 10. The motor 40 includes a stator 41 and a rotor 42, the stator 41 is fixed to the housing 10, and the rotor 42 is rotatable relative to the stator 41. The number of the compression units 20, 30 may be one or more. For example, the centrifugal compressor may be of a single-stage compression type, and only one compression unit may be provided. The centrifugal compressor may be of a multistage compression type in which a plurality of compression units 20 and 30 are provided. Each compression unit 20, 30 comprises a volute 100 and a centrifugal impeller 200. The scroll 100 is mounted to the housing 10, the centrifugal impeller 200 is mounted within the scroll 100, and the centrifugal impeller 200 is configured to rotate by the motor 40 to compress the airflow entering the scroll 100 and discharge it through the outlet of the scroll 100.

In a conventional centrifugal compressor, a diffuser is disposed at a downstream of a centrifugal impeller of each stage, the centrifugal impeller discharges an air flow into the diffuser, and the air flow is diffused by the diffuser and then enters a volute.

Compared with the traditional centrifugal compressor, the centrifugal compressor of the utility model omits a diffuser, and the centrifugal impeller 200 is directly arranged in the volute 100, so that the larger diffusion loss caused by the larger rotation degree of the airflow in the diffuser is avoided, the overall efficiency of the centrifugal compressor is improved, and the structure of the centrifugal compressor is more compact. Therefore, the structure is beneficial to realizing the miniaturization of the centrifugal compressor and keeping the high efficiency, so that the centrifugal compressor is suitable for being applied to a small central air conditioner such as a small water chilling unit or a multi-split air conditioner.

In some embodiments, such as shown in fig. 5 and 7, the centrifugal compressor may be of the two-stage compression type, with two compression units. It can be seen that one of the two compression units 20, 30 is necessarily a low pressure stage, and the other is a high pressure stage, as shown in fig. 5 and 6, the compression unit 20 on the left side of the drawing is a low pressure stage, and the compression unit 30 on the right side is a high pressure stage. 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 a connection pipe 90. Specifically, the inlet end of the connection pipe 90 is provided with a flange 91 to interface with the flange 130 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 90 is provided with a flange 92 to connect with the volute 100 of the compression unit 30 of the high pressure stage. It is preferable that the compression unit 20 of the low pressure stage and the compression unit 20 of the high pressure stage are respectively located at both axial sides of the motor 40, so that the centrifugal impellers 200 of the two compression units 20, 30 are respectively directly connected to the motor 40, and it is advantageous to partially cancel the axial forces of the two centrifugal impellers 200.

In some embodiments, the centrifugal compressor further comprises at least one radial magnetic bearing 60 and/or at least one axial magnetic bearing 80 mounted within the casing 10 to support the rotor 42 of the motor 40. As shown in fig. 6, the centrifugal compressor includes two radial magnetic bearings 60 to support the rotor 42 in a radial direction. The centrifugal compressor further comprises an axial magnetic bearing 80 to counteract the axial force generated by the movement of the centrifugal impeller 200 on the rotor 42. The magnetic suspension bearing is made by adopting a magnetic suspension principle and is an oilless bearing. Therefore, lubricating oil does not need to be added into the centrifugal compressor, so that the oil return problem of the compressor of a small and medium-sized refrigeration system is thoroughly solved (the conventional screw compressor, the scroll compressor and the rolling rotor compressor which are usually adopted are basically lubricated by oil), and the heat exchange efficiency of the heat exchanger is improved. And the magnetic suspension bearing is adopted, so that the centrifugal compressor has the advantages of small mechanical wear, low energy consumption, small noise, enhanced stability and longer service life.

Further, as shown in fig. 7, on the basis of the magnetic suspension bearing, a common radial bearing 70 may be further disposed at an axial end of the rotor 42 to support the end of the rotor 42 in an important manner, so that the end is more stable and the operational reliability of the centrifugal compressor is improved.

Fig. 8 is a schematic view of a compression unit 20 of fig. 1; fig. 9 is another angular schematic view of the compression unit 20 shown in fig. 8; fig. 10 is an exploded schematic view of the compression unit 20 shown in fig. 8.

In the embodiment of the present invention, the gas flow enters the flow passage defined by the volute 100 from the inlet of the volute 100, then enters the centrifugal impeller 200 in the flow passage of the volute 100, and finally flows out of the outlet of the volute 100 to enter the next-stage compression unit 30 or discharge compressor.

In some embodiments, as shown in fig. 8 to 10, the volute 100 defines an inlet flow passage 101, a volute flow passage 102 and an outlet flow passage 103 which are connected in sequence in the direction of the gas flow, i.e. the volute 100 flow passage is divided into three sections. The inlet of inlet flow path 101 forms the inlet of volute 100 as described herein, and the outlet of outlet flow path 103 forms the outlet of volute 100. The intake runner 101 extends in the axial direction (x-axis direction) of the centrifugal impeller 200. The volute flow path 102 has a flat shape with its thickness direction parallel to the axial direction of the centrifugal impeller 200. The outlet flow channel 103 gradually changes from flat to cylindrical from the junction with the volute flow channel 102 to the outlet of the volute 100. The centrifugal impeller 200 has an inlet 201 facing the inlet flow channel 101 and an outlet 202 facing the volute flow channel 102 for receiving air from the inlet flow channel 101 and compressing the air to discharge it to the volute flow channel 102.

In this embodiment, the flat volute 102 flattens the whole volute 100, which is beneficial to reducing the axial size of the centrifugal compressor and realizing the miniaturization of the compressor. More importantly, as the outlet flow channel 103 gradually changes from flat to cylindrical from the junction with the volute flow channel 102 to the outlet of the volute 100, the gas flow can have a very good diffusion effect in the process of entering the cylindrical and wide outlet flow channel 103 from the thin and flat volute flow channel 102. Moreover, because the outlet flow channel 103 gradually transits from the flat shape to the cylindrical shape from the joint with the volute flow channel 102 to the outlet of the volute 100, the transition is very smooth, unnecessary resistance loss of the air flow is reduced, and the cylindrical shape is also suitable for being connected with a downstream pipeline.

In some embodiments, as shown in FIG. 7, the intake runner 101 may include a tapered section 1011 with a gradually decreasing cross-section in the direction of airflow to improve the efficiency of air induction. Specifically, the tapered section 1011 may be made in the shape of a truncated cone as a whole, with a generatrix in the shape of an arc with a concave side facing the central axis direction of the intake runner 101. Further, the generatrix of the tapered section 1011 may be a straight line or a combination of various shapes. The intake runner 101 may be tapered as a whole, or may be a tapered section in a partial section, and a straight section in a partial section, the cross section of which does not change with the change of the axial position.

In some embodiments, as shown in fig. 10, the volute 100 may be a split structure including a volute body 110 and a cover plate 120 that are split along the axial direction of the inlet flow channel 101. The volute body 110 defines the aforementioned inlet flow passage 101, a first half of the volute flow passage 102 and an outlet flow passage 103, wherein the volute flow passage 102 is open to one side of the cover plate 120. The cover plate 120 covers an axial side of the volute body 110 to cover an open side of a first half of the volute 102 and define a second half of the volute 102, the first half of the volute 102 and the second half of the volute 102 opposing each other to form the completed volute 102. The rotation shaft 228 of the centrifugal impeller 200 is connected to the rotor 42 of the motor 40 through the center hole of the cover plate 120. In the present embodiment, the volute 100 is provided as a separate structure, and the volute body 110 and the cover plate 120 are separately machined to form the inlet flow passage 101, the volute flow passage 102 and the outlet flow passage 103 by machining. Compared with the existing integrally cast volute, in the embodiment, the surfaces of the inlet flow channel 101, the volute flow channel 102 and the outlet flow channel 103 are smoother, the uniformity of an internal flow field can be better met, the flow loss caused by the fact that the surfaces of the flow channels are too rough is reduced, and the operating efficiency of the centrifugal compressor is improved.

Further, as shown in fig. 7, two planes in the thickness direction of the volute flow channel 102 and the circumferential volute side face can be in rounded transition (R angle in fig. 7) so as to increase the strength of the volute, relieve the local stress concentration, eliminate the angular vortex and ensure the uniformity of the flow field. The size of R can be selected based on the thickness of the volute 102. The split configuration of the volute 100 facilitates the machining of the aforementioned rounded corners.

In some embodiments, the thickness of the volute flow path 102 is made greater than the outlet width B of the centrifugal impeller 200. The thickness of the volute 102 refers to the dimension of the volute in the axial direction (x-axis) of the centrifugal impeller 200, and the outlet width B of the centrifugal impeller 200 refers to the dimension of the outlet 202 of the centrifugal impeller 200 in the axial direction of the centrifugal impeller 200, and is specifically marked in fig. 7. Specifically, it was confirmed through many experiments by the inventors that the optimum effect can be obtained by setting the ratio of the thickness of the volute flow passage 102 to the outlet width of the centrifugal impeller 200 to 1.5 to 2.

The inventors have recognized that exhausting centrifugal impeller 200 directly to volute 100 results in an increased mach number of the airflow, a large centrifugal effect of the airflow that accumulates radially outward, resulting in an uneven flow field, resulting in large flow losses. In order to eliminate or at least alleviate the above adverse effects, the embodiment of the present invention particularly makes the thickness of the volute 102 greater than the outlet width B of the centrifugal impeller 200, so that after the airflow enters (the volute 102 of) the volute 100, the diffusion and the reduction speed are increased, the mach number of the airflow is reduced, the centrifugal effect is reduced, finally, the uniformity of the flow field at the outlet of the volute 100 is significantly increased, and finally, the efficiency of the compressor is improved.

In some embodiments, centrifugal impeller 200 is a strong back-curved shrouded impeller. The direction of rotation of the centrifugal impeller 200 is indicated by the arrow in fig. 2. Each blade of the centrifugal impeller 200 has a backward-curved structure, and the tip (end adjacent to the radially outer edge of the centrifugal impeller 200) of each blade is bent backward compared to the remaining section, so that each blade of the centrifugal impeller 200 has a strong backward-curved structure.

In the embodiment of the present invention, the centrifugal impeller 200 is strongly backward curved, so that the centrifugal impeller 200 applies more work to the air flow and converts the work into static pressure lifting, and the work is converted into speed increase. Because the absolute airflow angle of the outlet of the strong backward-bending centrifugal impeller is larger, if a traditional diffuser form is adopted, the airflow rotation degree is larger, and the diffusion loss is larger. The embodiment of the present invention employs the specially designed volute 100 to directly connect with the centrifugal impeller 200, which can effectively avoid this problem. It follows that the various improvements of the embodiments of the present invention do not act in isolation from each other, but act in combination. Specifically, in the embodiment of the present invention, the centrifugal impeller 200 is integrally and directly installed in the volute 100, the flow channel of the volute 100 is specially designed, and the improvements of the strong backward-bending centrifugal impeller 200 are combined together, so that the beneficial effects of various structural improvements are obtained, the respective adverse effects are greatly avoided, the overall efficiency of the centrifugal compressor is high, the structure is more compact, and the miniaturization is facilitated.

The second disk 220 is provided with a rotation shaft 228 having a mounting hole 2281 formed at the center thereof so as to be coupled to the rotor 42 by a screw 300. The first disk 210 is provided with an inlet 201 for the centrifugal impeller 200.

Thus, it should be appreciated by those skilled in the art that while various exemplary embodiments of the utility model have been shown and described in detail herein, many other variations or modifications which are consistent with the principles of this invention may be determined or derived directly from the disclosure of the present invention without departing from the spirit and scope of the utility model. Accordingly, the scope of the utility model should be understood and interpreted to cover all such other variations or modifications.

Claims (8)

1. A centrifugal impeller for a centrifugal compressor, characterized by comprising:

the turbine blade assembly comprises a first wheel disc, a second wheel disc and a third wheel disc, wherein a plurality of first blades arranged along the circumferential direction of the first wheel disc are convexly formed on one side surface of the first wheel disc; and

the second wheel disc is detachably connected with the first wheel disc, a plurality of second blades are formed on the surface, facing the first wheel disc, of one side of the second wheel disc in a protruding mode, and the plurality of first blades are in one-to-one butt joint with the plurality of second blades to form blades of the centrifugal impeller;

positioning columns are formed on at least part of the first blades and inserted into corresponding positioning holes formed in the second blades; and/or

Positioning columns are formed on at least part of the second blades and inserted into corresponding positioning holes formed in the first blades so as to constrain and position the first wheel disc and the second wheel disc;

at least part of the first blades and the corresponding second blades are provided with mounting holes so as to mutually fix the first wheel disc and the second wheel disc by utilizing a screw connection or riveting mode, and each mounting hole penetrates through the positioning column or the positioning hole.

2. The centrifugal impeller of claim 1,

the mounting hole and the axis of the positioning column or the positioning hole are arranged in a non-collinear mode.

3. The centrifugal impeller according to claim 1,

each first blade is provided with one positioning column, and each second blade is provided with one positioning hole; or

Each second blade is provided with one positioning column, and each first blade is provided with one positioning hole.

4. The centrifugal impeller of claim 1,

the positioning column and the positioning hole are circular or oval.

5. The centrifugal impeller of claim 1,

a first fillet is formed at the joint of the first blade and the rest part of the first wheel disc;

and a second fillet is formed at the joint of the second blade and the rest part of the second wheel disc.

6. The centrifugal impeller according to claim 5,

the radius of each first fillet is between 1/8 and 1 of the first vane height; and is

Each of the second rounded corners has a radius between 1/8 and 1 of the second vane height.

7. A centrifugal compressor characterized by comprising a centrifugal impeller according to any one of claims 1 to 6.

8. The centrifugal compressor of claim 7, comprising:

a housing;

the motor is arranged in the shell; and

at least one compression unit, each compression unit comprising a volute and a centrifugal impeller, the volute being mounted to the housing, the centrifugal impeller being mounted within the volute and configured to rotate under the drive of the motor to compress an air flow entering the volute and discharge it through an outlet of the volute.

Images