CN111692105A

CN111692105A - Cooling fan with outer rotor carbon fiber centrifugal impeller

Info

Publication number: CN111692105A
Application number: CN202010734777.6A
Authority: CN
Inventors: 屈小章; 翟方志; 张加贝; 刘梦安; 王艺
Original assignee: Hunan Lince Rolling Stock Equipment Co Ltd
Current assignee: Hunan Lince Rolling Stock Equipment Co Ltd
Priority date: 2020-07-28
Filing date: 2020-07-28
Publication date: 2020-09-22

Abstract

The invention provides a cooling fan with an outer rotor carbon fiber centrifugal impeller, which comprises a carbon fiber centrifugal impeller, a glass fiber air inlet channel, an outer rotor motor, an aluminum alloy shell and the like, wherein the outer rotor carbon fiber centrifugal impeller and the lightweight cooling fan for a locomotive air conditioner are connected through bolts to form the outer rotor carbon fiber centrifugal impeller; the stator of the outer rotor motor is arranged on the rear side plate of the aluminum alloy shell through a bolt; the glass fiber air inlet duct is arranged between the aluminum alloy casing and the carbon fiber centrifugal impeller and is mainly used for the flow guiding function, when the air conditioner is used, the design of the outer rotor carbon fiber centrifugal impeller, the glass fiber reinforced plastic air inlet duct and the like is realized, the load of an outer rotor motor is small, the reliability is high, and the air conditioner fan of the locomotive has the advantages of light overall weight, high fluid efficiency, convenience in installation and maintenance and the like.

Description

Cooling fan with outer rotor carbon fiber centrifugal impeller

Technical Field

The invention relates to the technical field of ventilation cooling equipment, in particular to a cooling fan with an outer rotor carbon fiber centrifugal impeller.

Background

The air conditioner is used for adjusting air performance of the rail transit locomotive and is one of key devices of the rail transit alternating-current transmission locomotive. When the air conditioner works, a large amount of heat is generated inside the air conditioner, in order to prevent the air conditioner from being damaged due to overheating and ensure the normal operation of the alternating current electric locomotive, a fan system is required to be adopted to forcedly dissipate heat of the air conditioner, and a centrifugal fan is an indispensable key component in the air conditioner system. In addition, along with the requirements of energy conservation, consumption reduction and reliability of rail transit, the requirements of light weight and reliability of equipment are higher and higher. The lightweight design technology of the air-conditioning centrifugal fan mainly comprises three methods, wherein the first method is to optimally design the structure, the existing air-conditioning centrifugal fan adopts a thin-wall structure, and the requirements of rail transit equipment on vibration and reliability are very high, so that the structure optimization space is smaller under the existing air-conditioning centrifugal fan; and secondly, replacing the original metal material with a fiber composite material with high strength ratio. At present, a centrifugal fan of an air conditioner of a locomotive is composed of an aluminum alloy impeller and a steel shell, the weight reduction of the impeller is crucial to the light weight design of the fan, and the lighter the impeller is, the light weight of the impeller can be realized, the load of the fan can be reduced, the vibration of the fan can be reduced, and the reliability of key components such as a fan bearing and the like can be improved; in addition, the side lead mode of the existing outer rotor motor fixes the power line in the shell through an iron wire, so that the power line is easily interfered with the rotating impeller, the safety is poor, and the maintenance and the overhaul are inconvenient.

Disclosure of Invention

The invention aims to design a carbon fiber composite outer rotor centrifugal impeller with a high strength ratio on the basis of the existing aluminum alloy outer rotor centrifugal impeller, is integrated in an outer rotor motor, adopts a rear end lead mode, is used in a light-weight centrifugal fan with high-performance air conditioner heat dissipation of an electric locomotive, meets the design requirement of a light-weight structure of the electric locomotive, and can effectively improve the reliability and the safety of the fan.

The technical scheme of the invention is as follows:

a cooling fan with an outer rotor carbon fiber centrifugal impeller is characterized by comprising a centrifugal impeller, an air inlet duct, an outer rotor motor and a casing which are combined to form a lightweight cooling fan for a system integrated locomotive air conditioner, wherein the carbon fiber centrifugal impeller and the outer rotor motor are connected through a first fastener to form the outer rotor carbon fiber centrifugal impeller; the stator of the outer rotor motor is arranged on the rear side plate of the shell through a second fastening piece; the shell comprises a flange plate, a mounting plate, an outlet side plate, a volute plate, an arc-shaped plate, a front side plate, an inner baffle, a rear side plate and the like; the air inlet duct is arranged between the casing and the centrifugal impeller and used for guiding flow.

Furthermore, the centrifugal impeller is a carbon fiber centrifugal impeller, the air inlet duct is a glass fiber air inlet duct, and the casing is an aluminum alloy casing.

Further, centrifugal impeller form by preceding rim plate, blade and back rim plate connection, preceding rim plate, blade and back rim plate-adopt T300 carbon fiber +/-45 preimpregnation cloth material to make, the thickness of fibrous layer is 0.2~0.4mm, the thickness of preceding rim plate and blade is 2~3mm, the preferential 2~4mm of thickness of back rim plate.

Furthermore, the front wheel disc is provided with a flow guide structure so as to improve the efficiency of the fan.

Furthermore, the thickness of the air inlet duct is 2-3 mm, the air inlet duct is made of 270g of glass fiber +/-45-degree prepreg cloth materials, and the thickness of the fiber layer is 0.2-0.4 mm.

Further, centrifugal impeller's blade about all the design have the boss with, preceding rim plate and back rim plate on set up with the notch of the first boss of blade and the adaptation of second boss, the blade is through realizing the overall stable equipment of centrifugal impeller in the notch of preceding rim plate and back rim plate of first boss and the assembly of second boss.

Further, the inlet angle B1 of the blade is 20-24 degrees, and the outlet angle B2 is 34-37 degrees; the width c of the inlet of the blade is 78-85 mm, and the width d of the outlet of the blade is 55-65 mm; the front wheel disc is provided with a flow guide structure, the radius R is 7-10 mm, and the width h is 10-15 mm.

Furthermore, the air inlet duct is installed on the front side plate of the casing through a third fastener, the size of a gap b between the centrifugal impeller and the air inlet duct is 2-4 mm, and the re-attaching width a is 7-9 mm.

Further, the front wheel disc, the blades, the rear wheel disc and the air inlet duct are subjected to bag pressure preforming and heating, pressurizing and curing processes respectively after the fiber layers are arranged and laid, pressurization is carried out for 2MPa for 1 hour when the temperature in the curing process reaches 80 ℃, and then the temperature is increased to 125 ℃ and the temperature is kept for 2 hours.

Further, preceding rim plate, blade, back rim plate carry on the location equipment that the gluing that beats of mutual seam crossing was glued, beat and glue the gap full, do not have the cull, polish after the bonding completion again to rim plate, back rim plate in the front adopt carbon fiber prepreg to reinforce in the boss position department of being connected with the blade, the prepreg of reinforcement is spread and is pasted total thickness 1~2mm, adopts glued membrane to connect.

Further, the centrifugal impeller is solidified by adopting integral vacuum bag pressing positioned by a tool after being assembled, the centrifugal impeller is pressurized to 2MPa for heat preservation for 1h when the temperature reaches 80 ℃, then the centrifugal impeller is heated to 125 degrees and is solidified for heat preservation for 2h, in the integral solidification process of the impeller, the blades, the carbon fibers of the front wheel disc and the rear wheel disc complete secondary high-temperature forming, and the carbon fiber prepreg at the joints of the blades, the front wheel disc and the rear wheel disc also completes high-temperature forming.

The invention has the advantages that the outer rotor motor has the problem of small bearing capacity, the carbon fiber with high strength ratio and lighter weight is used in the design of the centrifugal impeller of the outer rotor of the air-conditioning fan, the weight of the impeller is reduced, the load of the outer rotor motor is reduced, the vibration of the fan is reduced, the service life and the reliability of the outer rotor motor are favorably improved, the light-weight design of the fan is realized, and the requirements of light weight and reliability of track traffic equipment are met.

The front wheel disc, the blades and the rear wheel disc of the impeller adopt a specific layering mode, so that the split forming of the impeller is realized, the complexity of the integral forming is effectively reduced, the manufacturing cost of a die and the cost of raw materials are reduced, and the research and development cost is effectively reduced.

The carbon fiber laying centrifugal impeller is adopted, so that the problem of welding forming deformation of the metal impeller is solved, adverse factors such as gaps and defects in the material are overcome, the stability of the impeller structure including a dynamic balance process is improved, and the consistency of fan products is improved.

The glass fiber with reduced cost is used for the air inlet duct structural design, thereby being beneficial to reducing the weight of the air inlet duct, reducing the cost and further realizing the light weight design of the fan.

The inlet and outlet angles, the inlet and outlet widths and the like of the impeller are relatively limited, so that the performance of the fan is ensured, and in addition, the flow guide structure is additionally arranged on the front wheel disc, so that the fluid performance of the fan is more favorably improved.

The carbon fiber impeller and the outer rotor motor are effectively integrated, so that the motor bearing of the outer rotor can be obviously reduced, and the service life and the reliability of the outer rotor motor are improved; and the lead mode of the outer rotor motor is changed from the side surface to the rear end lead, so that the safety of the fan and the convenience of maintenance are improved.

The impeller and the air inlet duct of the fan are made of non-metal materials instead of traditional metal materials, the shell structure is made of light aluminum alloy materials instead of original steel materials, the weight of the fan is reduced by more than 25% by continuously optimizing the structure, and the requirement of light weight of rail transit equipment is effectively met.

Drawings

Fig. 1 is a structural diagram of a cooling fan assembly according to an embodiment of the present invention.

Fig. 2 is a front view and a right side view of an outer rotor carbon fiber impeller according to an embodiment of the present invention.

Fig. 3 is a structural schematic view of a first boss and a second boss of the impeller in fig. 2.

Fig. 4 is a schematic view of the rear disk notch structure of the impeller of fig. 2.

Fig. 5 is a schematic structural view of an air inlet duct according to an embodiment of the present invention.

Fig. 6 is a front view and a right side view of the rotor motor according to the embodiment of the present invention.

Fig. 7 is a front view and a right side view of a cabinet according to an embodiment of the present invention.

In the drawings: the centrifugal impeller comprises a centrifugal impeller 1, an air inlet duct 2, an outer rotor motor 3, a machine shell 4, a first fastener 5, a second fastener 6, a third fastener 7, a front wheel disc 1-1, blades 1-2, a rear wheel disc 1-3, notches 1-4, a flow guide structure 1-1-1, a first boss 1-2-1, a second boss 1-2-2, a stator 3-2, a front side plate 4-7 and a rear side plate 4-9.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

The embodiment of the cooling fan with the outer rotor carbon fiber centrifugal impeller shown in fig. 1 to 7 is characterized in that the cooling fan comprises a centrifugal impeller 1, an air inlet duct 2, an outer rotor motor 3 and a casing 4 which are combined to form a lightweight cooling fan for the air conditioner of the system integrated locomotive, wherein the centrifugal impeller 1 and the outer rotor motor 3 are connected through a first fastener 5 to form the outer rotor carbon fiber centrifugal impeller; the stator 3-2 of the outer rotor motor 3 is arranged on the rear side plate 4-9 of the machine shell 4 through a second fastening piece 6; the shell comprises a flange plate, a mounting plate, an outlet side plate, a volute plate, an arc-shaped plate, a front side plate, an inner baffle, a rear side plate and the like; the air inlet duct 2 is arranged between the casing 4 and the centrifugal impeller 1 and used for guiding flow.

In this embodiment, the centrifugal impeller 1 is a carbon fiber centrifugal impeller, the air inlet duct 2 is a glass fiber air inlet duct, and the casing 4 is an aluminum alloy casing.

In this embodiment, the centrifugal impeller 1 is formed by connecting a front wheel disc 1-1, blades 1-2 and a rear wheel disc 1-3, the front wheel disc 1-1, the blades 1-2 and the rear wheel disc 1-3 are made of T300 carbon fiber ± 45 ° prepreg cloth material, a thickness of a fiber layer is 0.2mm (in other embodiments, a thickness of the fiber layer may also be 0.2 to 0.4mm, for example, 0.3 mm), a thickness of the front wheel disc 1-1 and the blades 1-2 is 2.5mm (in other embodiments, a thickness of the front wheel disc 1-1 and the blades 1-2 may also be 2 to 3mm, for example, 2 mm), and a thickness of the rear wheel disc 1-3 is preferably 3mm (in other embodiments, a thickness of the rear wheel disc 1-3 may also be 2 to 4mm, for example, 3.5 mm).

In this embodiment, preceding rim plate is equipped with the water conservancy diversion structure to improve fan efficiency.

In this embodiment, the thickness of the air inlet duct 2 is 2mm (in other embodiments, the thickness of the air inlet duct 2 may also be 2 to 3mm, for example, 2.8 mm), the air inlet duct is made of 270g of glass fiber ± 45 ° prepreg cloth material, and the thickness of the fiber layer is 0.2mm (in other embodiments, the thickness of the fiber layer may also be 0.2 to 0.4mm, for example, 0.3 mm).

In this embodiment, bosses 1-2-1 and 1-2-2 are respectively designed at upper and lower edges of a blade 1-2 of the centrifugal impeller 1, notches 1-4 matched with a first boss 1-2-1 and a second boss 1-2-2 of the blade are formed in the front wheel disc 1-1 and the rear wheel disc 1-3, and the blade 1-2 is assembled into the notches 1-4 of the front wheel disc 1-1 and the rear wheel disc 1-3 through the first boss 1-2-1 and the second boss 1-2-2 to realize the integral stable assembly of the centrifugal impeller 1.

In the present embodiment, the inlet angle B1 of the blade 1-2 is 22.8 °, and the outlet angle B2 is 35 ° (in the remaining embodiments, the inlet angle B1 of the blade 1-2 may also be 20 ° to 24 °, for example, 22 °; and the outlet angle B2 may also be 34 ° to 37 °, for example, 36 °); the inlet width c of the blade 1-2 is 81mm, and the outlet width d is 60mm (in other embodiments, the inlet width c of the blade 1-2 may also be 78-85 mm, such as 83 mm; and the outlet width d may also be 55-65 mm, such as 63 mm); the front wheel disc 1-1 is provided with a flow guiding structure 1-1-1, the radius R is 8mm, and the width h is 12mm (in other embodiments, the flow guiding structure 1-1-1 of the front wheel disc 1-1 may also have a radius R of 7-10 mm, such as 9mm, and a width h of 10-15mm, such as 13 mm).

In this embodiment, the air inlet duct 2 is mounted on the front side plate 4-7 of the casing 4 by a third fastening member 7, a gap b between the centrifugal impeller 1 and the air inlet duct 2 is 3mm, and a reattachment width a is 8mm (in other embodiments, the gap b may also be 2-4 mm, such as 2.5mm, and the reattachment width a may also be 7-9 mm, such as 7.5 mm).

In the embodiment, the air duct outlet diameter J2 of the air inlet duct 2 is 165-172 mm, the installation maximum diameter J3 is 275-285 mm, the width J1 is 28-30mm, the embodiment J2 is 170mm, the J3 is 280mm, and the J1 is 29 mm.

In this embodiment, the blanks of the front wheel disc 1-1, the blades 1-2, the rear wheel disc 1-3 and the air inlet duct 2 after the arrangement and the laying of the fiber layers are subjected to bag-pressing preforming and heating, pressurizing and curing processes, the temperature in the curing process is up to 80 ℃, the pressure is applied under 2MPa, the temperature is kept for 1h, then the temperature is increased to 125 ℃, the temperature is kept for 2h, after the curing and forming, the blanks of the front wheel disc 1-1, the blades 1-2, the rear wheel disc 1-3 and the glass fiber air inlet duct 2 are respectively removed from a curing mold, and then numerical control processing is performed.

In this embodiment, after the numerical control processing is completed, the front wheel disc 1-1, the blades 1-2 and the rear wheel disc 1-3 are positioned and assembled by gluing and bonding at the mutual joint, the gluing gap is full and has no residual glue, the front wheel disc 1-1 and the rear wheel disc 1-3 are polished after the bonding is completed, carbon fiber prepreg is adopted at the position of the boss connected with the blades 1-2 for reinforcement, the reinforced prepreg is paved and adhered with a total thickness of 1.5mm (in other embodiments, the paving and adhering total thickness can be 1-2 mm, for example, 1.8 mm), and the carbon fiber prepreg and the rear wheel disc are connected by glue films.

In this embodiment, the centrifugal impeller 1 is assembled and then cured by using an integral vacuum bag positioned by a tool, the centrifugal impeller is pressurized to 2MPa and insulated for 1h when the temperature reaches 80 ℃, then heated to 125 ℃ and insulated and cured for 2h, in the integral curing process of the impeller, the blades 1-2 and the carbon fibers of the front wheel disc 1-1 and the rear wheel disc 1-3 complete secondary high-temperature forming, and the blades 1-2 and the carbon fiber prepreg at the joints of the front wheel disc 1-1 and the rear wheel disc 1-3 also complete high-temperature forming.

It should be noted that all the above curing processes are performed by gradually pressurizing to 2MPa at 80 ℃ and maintaining for 1h, then heating to 125 ℃ and maintaining for 2 h.

When the outer rotor carbon fiber impeller is used, 1, when the outer rotor carbon fiber impeller is produced, only a simple die needs to be manufactured, an integral complex die and machining equipment are not needed, and the production process is few and simple. Compared with the weight of carbon steel, the total weight of the manufactured carbon fiber impeller is reduced by more than 60%, and compared with an aluminum alloy impeller, the weight is reduced by more than 25%, so that the vibration of the air conditioner fan is greatly reduced, and the service life and the reliability of the outer rotor motor 3 are improved.

2. The inlet angle B1, the outlet angle B2, the inlet width c and the outlet width d of the blade are limited relatively, so that the pressure and flow parameters of the outer centrifugal impeller 1 and the cooling fan can be effectively ensured, in addition, the design that the front wheel disc 1-1 is provided with the flow guide structure 1-1-1 enables a medium flow field to be more reasonable, and the overall performance of the centrifugal impeller and the cooling fan is effectively improved.

3. The outer rotor motor 3 consists of a rotor 3-1, a stator 3-2, a power supply outlet 3-3, a temperature control outlet 3-4 and a power supply lead 3-5, wherein the power supply lead 3-5 mode is changed from the original side lead to the rear end lead, and the protection grade of the outer rotor motor is not lower than IP 54; the side lead mode of current external rotor electric machine, the side lead is fixed the power cord through the iron wire in casing inside, interferes with rotatory impeller easily, and the security is poor, moreover the maintenance overhaul inconvenient etc.. The side lead is changed into the rear lead, so that the reliability and the safety of the product are improved, the installation is simple, and the maintenance and the overhaul are convenient.

4. The shell 4 is made of aluminum alloy instead of steel, so that light weight design of the product is realized.

5. The outer rotor motor 3 has the problem of small bearing capacity, and the carbon fiber with high strength ratio and lighter weight is used in the design of the centrifugal impeller of the outer rotor of the air-conditioning fan, so that the weight of the impeller is reduced, the load of the outer rotor motor 3 is reduced, the vibration of the fan is reduced, the service life and the reliability of the outer rotor motor 3 are improved, the light-weight design of the fan is realized, and the requirements of light weight and reliability of track traffic equipment are met.

6. The front wheel disc 1-1, the blades 1-2 and the rear wheel disc 1-3 of the centrifugal impeller 1 adopt a specific layering mode, so that the split molding of the impeller is realized, the complexity of the integral molding is effectively reduced, the manufacturing cost of a mold and the cost of raw materials are reduced, and the research and development cost is effectively reduced.

7. The carbon fiber laying centrifugal impeller 1 is adopted, so that the problem of welding forming deformation of a metal impeller is prevented, adverse factors such as gaps and defects existing in the material are compensated, the stability of the impeller structure including a dynamic balance process is improved, and the consistency of fan products is improved.

8. The glass fiber with reduced cost is used for the structural design of the air inlet duct 2, which is beneficial to reducing the weight of the air inlet duct 2, reducing the cost and further realizing the light weight design of the fan.

9. The inlet and outlet angles, the inlet and outlet widths and the like of the centrifugal impeller 1 are relatively limited, so that the performance of the fan is ensured, and in addition, the flow guide structure is additionally arranged on the front wheel disc 1-1, so that the fluid performance of the fan is more favorably improved.

In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.

Claims

1. A cooling fan with an outer rotor carbon fiber centrifugal impeller is characterized by comprising a centrifugal impeller (1), an air inlet duct (2), an outer rotor motor (3) and a casing (4) which are combined to form a lightweight cooling fan for a system integration locomotive air conditioner, wherein the centrifugal impeller (1) and the outer rotor motor (3) are connected through a first fastener (5) to form the outer rotor carbon fiber centrifugal impeller; a stator (3-2) of the outer rotor motor (3) is arranged on a rear side plate (4-9) of the machine shell (4) through a second fastening piece (6); the air inlet duct (2) is arranged between the casing (4) and the centrifugal impeller (1) and used for guiding flow.

2. The cooling fan with the outer rotor carbon fiber centrifugal impeller is characterized in that the centrifugal impeller (1) is formed by connecting a front wheel disc (1-1), blades (1-2) and a rear wheel disc (1-3), the front wheel disc (1-1), the blades (1-2) and the rear wheel disc (1-3) are made of T300 carbon fiber +/-45-degree prepreg cloth materials, the thickness of a fiber layer is 0.2-0.4 mm, the thicknesses of the front wheel disc (1-1) and the blades (1-2) are 2-3 mm, and the thickness of the rear wheel disc (1-3) is preferably 2-4 mm.

3. The cooling fan with the outer rotor carbon fiber centrifugal impeller according to claim 1, wherein the thickness of the air inlet duct (2) is 2-3 mm, the cooling fan is made of 270g of glass fiber +/-45 degrees prepreg cloth material, and the thickness of the fiber layer is 0.2-0.4 mm.

4. A cooling fan with an outer rotor carbon fiber centrifugal impeller in accordance with claim 2, it is characterized in that the upper edge and the lower edge of a blade (1-2) of the centrifugal impeller (1) are respectively provided with a lug boss (1-2-1) and a lug boss (1-2-2), the centrifugal impeller is characterized in that notches (1-4) matched with the first boss (1-2-1) and the second boss (1-2-2) of the blade are formed in the front wheel disc (1-1) and the rear wheel disc (1-3), and the blade (1-2) is assembled into the notches (1-4) of the front wheel disc (1-1) and the rear wheel disc (1-3) through the first boss (1-2-1) and the second boss (1-2-2) to achieve integral stable assembly of the centrifugal impeller (1).

5. The cooling fan with the external rotor carbon fiber centrifugal impeller of claim 4, wherein the inlet angle B1 of the blades (1-2) is 20-24 degrees, and the outlet angle B2 is 34-37 degrees; the width c of the inlet of the blade (1-2) is 78-85 mm, and the width d of the outlet is 55-65 mm; the front wheel disc (1-1) is provided with a flow guide structure (1-1-1), the radius R is 7-10 mm, and the width h is 10-15 mm.

6. The cooling fan with the outer rotor carbon fiber centrifugal impeller according to claim 3, wherein the air inlet duct (2) is mounted on a front side plate (4-7) of the casing (4) through a third fastening member (7), a gap b between the centrifugal impeller (1) and the air inlet duct (2) has a size of 2-4 mm, and a reattachment width a is 7-9 mm.

7. The cooling fan with the outer rotor carbon fiber centrifugal impeller according to claim 2 or 3, wherein blanks of the front wheel disc (1-1), the blades (1-2), the rear wheel disc (1-3) and the air inlet duct (2) after the fiber layers are arranged and laid are subjected to bag pressure preforming and heating and pressurizing solidification processes respectively, the blanks are pressurized for 2MPa for 1 hour when the temperature of the solidification process reaches 80 ℃, and then are heated to 125 ℃ and are subjected to heat preservation for 2 hours.

8. The cooling fan with the outer rotor carbon fiber centrifugal impeller is characterized in that the front wheel disc (1-1), the blades (1-2) and the rear wheel disc (1-3) are positioned and assembled in a gluing mode at the mutual joint, gluing gaps are full and have no residual glue, grinding is carried out after gluing is finished, carbon fiber prepreg is adopted at the positions of the front wheel disc (1-1) and the rear wheel disc (1-3) and the positions of connecting bosses with the blades (1-2) for reinforcement, the total thickness of the reinforced prepreg paving paste is 1-2 mm, and glue films are adopted for connection.

9. The cooling fan with the outer rotor carbon fiber centrifugal impeller is characterized in that after the centrifugal impeller (1) is assembled, the centrifugal impeller is cured by adopting an integral vacuum bag positioned by a tool, the temperature is 80 ℃, the pressure is increased to 2MPa, the heat is preserved for 1h, then the temperature is increased to 125 ℃, the heat is preserved and cured for 2h, during the integral curing process of the impeller, the carbon fibers of the blade (1-2), the front wheel disc (1-1) and the rear wheel disc (1-3) are subjected to secondary high-temperature forming, and the carbon fiber prepreg at the joint of the blade (1-2), the front wheel disc (1-1) and the rear wheel disc (1-3) is also subjected to high-temperature forming.