CN112855609A

CN112855609A - Fan and motor

Info

Publication number: CN112855609A
Application number: CN201911191931.3A
Authority: CN
Inventors: 贾喜勤; 李广; 罗慧强; 刘永强; 姬春霞; 苏莫明; 张洁
Original assignee: CRRC Yongji Electric Co Ltd
Current assignee: CRRC Yongji Electric Co Ltd
Priority date: 2019-11-28
Filing date: 2019-11-28
Publication date: 2021-05-28
Anticipated expiration: 2039-11-28
Also published as: WO2021103050A1; CN112855609B

Abstract

The invention provides a fan and a motor, wherein the fan comprises a wheel disc and a plurality of blades, and the wheel disc is connected with the motor; the blades protrude out of the wheel disc along the axial direction of the wheel disc, and the blades extend along the radial direction of the wheel disc; the wheel disc has at least a first circumference and a second circumference, the radius of the first circumference is smaller than the radius of the second circumference; the plurality of blades comprise a plurality of first blades and a plurality of second blades, the plurality of first blades are arranged at intervals along the first circumference, the plurality of second blades are arranged at intervals along the second circumference, and the plurality of first blades and the plurality of second blades are arranged in a staggered manner along the circumferential direction of the wheel disc; at least part of the windward side of the second blade corresponds to the first blade, and the second blade and the first blade form a blade unit.

Description

Fan and motor

Technical Field

The invention relates to the technical field of motors, in particular to a fan and a motor.

Background

The cooling fan equipped for the generator, the traction motor and other motors can be a radial straight blade fan, and the radial straight blade fan is not influenced by the rotation direction of the motor and is convenient to use.

The radial straight blade fan comprises a wheel disc and a plurality of blades, wherein the wheel disc is connected with a rotating shaft of the motor, and the plurality of blades are arranged at intervals along the circumferential direction of the wheel disc; wherein, the blade is along the axial protrusion rim plate of rim plate, and extends along the radial of rim plate. The rotating shaft drives the fan to rotate, and the pressure surface of the windward side of the blade drives air to flow.

The radial straight blade fan is noisy when rotating.

Disclosure of Invention

In view of the above problems, the present invention provides a fan and a motor, which have low noise when the fan is rotated.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

a first aspect of the present invention provides a fan comprising: the wheel disc is connected with the motor; the blades protrude out of the wheel disc along the axial direction of the wheel disc, and the blades extend along the radial direction of the wheel disc; the wheel disc has at least a first circumference and a second circumference, the radius of the first circumference is smaller than the radius of the second circumference; the plurality of blades comprise a plurality of first blades and a plurality of second blades, the plurality of first blades are arranged at intervals along the first circumference, the plurality of second blades are arranged at intervals along the second circumference, and the plurality of first blades and the plurality of second blades are arranged in a staggered manner along the circumferential direction of the wheel disc; at least part of the windward side of the second blade corresponds to the first blade, and the second blade and the first blade form a blade unit.

The fan as described above, wherein the plurality of blades includes a blade group disposed at intervals in the circumferential direction, the blade group includes one second blade and two first blades, and the two first blades are disposed on both sides of the second blade; the circumferential directions include a first circumferential direction and a second circumferential direction, the first circumferential direction and the second circumferential direction being opposite; in the first circumferential direction, the second blade and the first blade on the windward side thereof form a first blade unit, and in the second circumferential direction, the second blade and the other first blade form a second blade unit.

The fan as described above, wherein an end of the second blade close to the first blade and an end of the first blade close to the second blade are located on the same circumference.

The fan as described above, wherein one of the first blades and the second blade form a first included angle, and the other of the first blades and the second blade form a second included angle, and the first included angle is equal to the second included angle.

The fan as described above, wherein two first blades form a fourth included angle, two adjacent first blades in two adjacent blade groups form a third included angle, and the third included angle is greater than or equal to the fourth included angle.

The fan as described above, wherein the outer edges of the blades facing away from the wheel disc axis are notched.

The fan comprises a front disc, wherein the front disc and the wheel disc are coaxially arranged, and a plurality of blades are connected with the wheel disc and the front disc; the front disc is provided with an air inlet, and an air outlet gap is formed between the edge of the front disc and the edge of the wheel disc.

The fan comprises a wheel disc, a front disc and a fan blade, wherein the wheel disc comprises a body and an air outlet part, the body is provided with a connecting part connected with a motor, and the blade is connected between the air outlet part and the front disc; the air outlet part and the front disc are arranged at an acute angle.

The fan comprises a body, wherein the body further comprises a conical shell, the connecting part is located at the small end of the conical shell, and the air outlet part extends from the edge of the large end of the conical shell to one side departing from the axis of the wheel disc.

Compared with the prior art, the fan provided by the embodiment of the invention has the following advantages: the fan includes rim plate and a plurality of blade, and the blade is protruding and along the radial extension of rim plate along rim plate volume circumference, is radial straight blade form. Wherein, the blade includes first blade and second blade, first blade sets up along first circumference interval, the second blade sets up in first blade periphery and along second circumference interval, along the circumference of rim plate, every second blade all staggers with first blade, make the fan when rotatory, the second blade can form the blade unit with the adjacent first blade in windward side, the outlet angle of blade unit is less than 90, the more radial straight blade of angle of attack of blade unit diminishes, avoid blade unit leeward side air current and suction surface separation, blade unit leeward side can form stable air current swirl, the swirl noise reduces, fan small in noise.

A second aspect of the present invention provides an electric machine comprising: the fan comprises a machine shell, a stator assembly, a rotor assembly and the fan, wherein the stator assembly and the rotor assembly are arranged in the machine shell, and the fan is connected with a rotating shaft of the rotor assembly.

In addition to the technical problems solved by the embodiments of the present invention, the technical features constituting the technical solutions, and the advantages brought by the technical features of the technical solutions described above, other technical problems solved by the fan and the motor provided by the embodiments of the present invention, other technical features included in the technical solutions, and advantages brought by the technical features will be further described in detail in the detailed description.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

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

fig. 2 is a first schematic structural diagram of another fan according to a first embodiment of the present invention;

fig. 3 is a second schematic structural diagram of another fan according to the first embodiment of the present invention;

fig. 4 is a partial sectional structural view of fig. 2 and 3.

Reference numerals:

10: a wheel disc;

11: a first circumference;

12: a second circumference;

13: a body;

131: a connecting portion;

132: a conical housing;

14: an air outlet part;

21: a first blade;

22: a second blade;

23: a blade group;

231: a first blade unit;

232: a second blade unit;

24: a notch;

30: a front plate;

31: an air inlet;

40: an air outlet gap;

x: a first circumferential direction;

y: a second circumferential direction;

α: a first included angle;

beta: a second included angle;

θ: a third included angle;

γ: and a fourth angle.

Detailed Description

In order to make the aforementioned objects, features and advantages of the embodiments of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The blade inlet angle refers to an included angle between the outer edge of the blade and the tangential direction of the circumference, the blade inlet angle of the radial straight blade is 90 degrees, the inlet airflow angle refers to an included angle between the relative speed direction of airflow entering the flow channel and the circumferential direction, and the difference between the blade inlet angle and the inlet airflow angle is an attack angle. The larger the attack angle is, the more the airflow is separated from the suction surface on the leeward side of the blade, and the separated airflow forms unstable airflow vortex to cause vortex noise, so that the noise is large when the fan rotates.

Example one

To solve the above problems, fig. 1 is a schematic structural diagram of a fan according to a first embodiment of the present invention, fig. 2 is a schematic structural diagram of another fan according to the first embodiment of the present invention, fig. 3 is a schematic structural diagram of another fan according to the first embodiment of the present invention, fig. 4 is a schematic structural diagram of a part of cross-sectional views of fig. 2 and fig. 3, and referring to fig. 1 to fig. 4, the present embodiment provides a fan including: the rotary table 10 is connected with the motor; the blades protrude out of the wheel disc 10 along the axial direction of the wheel disc 10, and the blades extend along the radial direction of the wheel disc 10; the wheel disc 10 has at least a first circumference 11 and a second circumference 12, the radius of the first circumference 11 being smaller than the radius of the second circumference 12; the plurality of blades comprise a plurality of first blades 21 and a plurality of second blades 22, the plurality of first blades 21 are arranged at intervals along a first circumference 11, the plurality of second blades 22 are arranged at intervals along a second circumference 12, and the plurality of first blades 21 and the plurality of second blades 22 are arranged in a staggered manner along the circumferential direction of the wheel disc 10; at least part of the second blades 22 corresponds to the first blades 21 on the windward side, and the second blades 22 and the first blades 21 form a blade unit.

Specifically, the fan is applied to motors such as a generator and a traction motor, and the rotation of the fan can take away heat generated by the motor to cool the motor.

The fan can include the rim plate 10 and a plurality of blades, and rim plate 10 is connected with the pivot of motor, and the material of rim plate 10 can be plastics, also can be metal, for example iron or stainless steel etc. high strength.

The blades are spaced circumferentially along the disk 10. The blades may be located on the outer edge of the disk 10 or may be located on the side of the disk 10. Wherein, the blade can be connected with the wheel disc 10 by welding, and can also be made by integral molding.

For noise reduction, the blade can divide into a plurality of parts, along circumference, outside blade and the adjacent inboard blade in windward side form the blade unit, and the blade unit is the contained angle setting with arbitrary blade, and the export erection angle of blade unit diminishes, and the attack angle diminishes, and blade unit leeward side can form stable air current swirl, and the swirl noise is little. Illustratively, three circumferences of blades may be provided on the impeller 10, and the blades are divided into three parts, and the blades on the three circumferences are staggered, for example, the blades may be arranged in a V-shape, and the blades on the inner circumference are located in front of the airflow of the blades on the adjacent outer circumference.

Alternatively, in the embodiment, the blade is divided into two parts for illustration, the disk 10 is provided with a first circumference 11 and a second circumference 12, the blade includes a first blade 21 and a second blade 22, the first blade 21 is disposed along the first circumference 11 at intervals, and the second blade 22 is disposed around the first blade 21 and disposed along the second circumference 12 at intervals. Each second blade 22 is staggered with the first blade 21 along the circumferential direction of the disk 10, so that when the fan rotates, the windward side of a part of the second blades 22 can correspond to one first blade 21 and form a blade unit, and at this time, the rest of the second blades 22 can be used as radial straight blades to drive air to flow; or each second vane 22 may correspond to one first vane 21 to form a vane unit, in this case, the number of the second vanes 22 may be the same as the number of the first vanes 21, the number of the second vanes 22 may be smaller than the number of the first vanes 21, and the excessive first vanes 21 may drive the air flow as straight radial vanes.

To the blade unit, the center-connecting line of first blade 21 and second blade 22 is the contained angle setting with second blade 22, and when the fan was just passed or was changeed, the exit angle of blade unit was less than 90, and corresponding its angle of attack is less than the angle of attack of radial straight blade, avoids the air current to break away from the suction surface of blade unit leeward side, and the leeward side of blade unit can form stable wing type air current swirl, reduces the swirl noise, has also reduced the noise of fan.

The blade unit may include two or more blades according to the number of circumferences provided on the disk 10, and the embodiment is not limited. In order to enable the blade units to reduce the swirl noise when the fan rotates forwards or backwards, the two blade units may be combined into one blade group, wherein the plurality of blades include the blade group 23 arranged at intervals along the circumferential direction, the number of the blades in the blade group 23 may be three or more according to the number of the circumferences, the embodiment is described by taking the blade group 23 including three blades as an example, the number of the blades is small, and the manufacturing is simple. The blade group 23 may include two second blades 22 and one first blade 21, or as shown in the present embodiment, the blade group 23 includes one second blade 22 and two first blades 21, and the two first blades 21 are disposed on both sides of the second blade 22.

Since the circumferential directions include the first circumferential direction X and the second circumferential direction Y, which are opposite to each other, in order to protect the fan from the forward rotation or the reverse rotation of the motor, the blade assembly 23 should be able to cool the motor when the motor rotates in both the forward rotation and the reverse rotation, that is, the second blade 22 forms the first blade unit 231 with the first blade 21 on the windward side thereof in the first circumferential direction X, and the second blade 22 forms the second blade unit 232 with the other first blade 21 in the second circumferential direction Y.

For convenience of description, the first circumferential direction X is taken as a fan normal rotation, and the second circumferential direction Y is taken as a fan reverse rotation. Referring to fig. 1, when the fan rotates reversely, the second blade 22 and the first blade 21 on the left side thereof form a second blade unit 232, the second blade unit 232 drives the air flow as a whole, and the first blade 21 on the right side of the second blade 22 drives the air flow as an independent blade. When the fan is rotated in the normal direction, the second blade 22 and the first blade 21 on the right side thereof form a first blade unit 231, the first blade unit 231 drives the air flow as a whole, and the first blade 21 on the left side of the second blade 22 drives the air flow as an independent blade.

It can be understood that, when the number of blades in the blade unit is infinite, and the extension length of the blades along the radial direction is infinite, the blade unit can be evolved into a backward-curved blade, the blade inlet angle of the backward-curved blade fan is smaller than 90 °, correspondingly, the attack angle of the backward-curved blade fan is smaller than that of the radial straight blade fan, so that the air flow is prevented from being separated from the suction surface on the leeward side of the blade unit, the air flow can form a stable air flow vortex on the leeward side, and the vortex noise and the rotational impact noise are lower than those of the existing radial straight blade fan. The present embodiment utilizes this principle, and takes the form of a blade unit including two blades, and the noise of the fan is low.

Specifically, when the fan rotates reversely, the second blade unit 232 and the first blade 21 on the right side can respectively drive the air to flow and respectively form stable airfoil-shaped airflow vortexes, wherein the blade size of the first blade 21 on the right side is smaller than that of the existing straight blade, and the airfoil-shaped airflow vortexes formed by the first blade unit are more stable in shape, size, stability and the like than those formed by the existing radial straight blade, and the noise is low. And the shape of the airfoil-shaped airflow vortex formed by the second blade unit 232 is more stable than that formed by the right-side straight blade, the size is smaller, and the vortex noise is lower. It should be understood that when the fan rotates forward, the airflow vortexes formed by the first blade unit 231 and the left first blade 21 are the same as those described above, and the description of this embodiment is omitted. Therefore, as a whole, the blade group 23 has lower swirl noise than one radial straight blade at the time of forward and reverse rotation of the fan.

In order to prevent the flow rate of the fan cooling air from decreasing, in the present embodiment, the sum of the radial extension lengths of the first blade 21 and the second blade 22 may be equal to the radial length of the existing radial straight blade. Since the blade sizes of the first blade 21 and the second blade 22 are smaller than the area of the conventional radial straight blade, the impact noise between the first blade 21 and the air and the impact noise between the second blade 22 and the air are smaller than the impact noise of the conventional straight blade, and the noise generated when the fan provided by the embodiment rotates is further reduced.

It can be understood that one second blade 22 may be further disposed between two second blades 22, so that the second blades 22 may correspond to the first blades 21 one by one, when the fan rotates forward and backward, each second blade 22 may correspond to one first blade 21 and form a blade unit, and the vortex noise and the rotational impact noise of the fan are low. If the fan noise of the blade group 23 provided by the embodiment includes one second blade 22 and two first blades 21, which meets the use requirement, the one second blade 22 may not be additionally arranged between the two second blades 22, and the manufacturing cost is low.

When a gap is formed between the first blade 21 and the second blade 22 in the radial direction of the disk 10, air passes through the gap between the first blade 21 and the second blade 22 when the fan rotates, and stable airflow swirl is not formed on the leeward side of the first blade 21 and the second blade 22, which causes loud noise. Therefore, the first blade 21 and the second blade 22 can be overlapped along the radial direction of the disk 10, and optionally, one end of the second blade 22 close to the first blade 21 and one end of the first blade 21 close to the second blade 22 are located on the same circumference, so that the structure is compact.

In order to make the noise of the fan uniform when the fan rotates forward and backward, two first blades 21 may be symmetrically disposed on two sides of the second blade 22, specifically, one of the first blades 21 and the second blade 22 form a first included angle α, the other first blade 21 and the second blade 22 form a second included angle β, the first included angle α and the second included angle β are equal, the size of the data disk 10 and the number of the blade groups 23, the sizes of the first included angle α and the second included angle β may float in different ranges, and for example, the angles of the first included angle α and the second included angle β may be 3 ° to 10 °.

Considering that the size of the airfoil flow vortex formed by a single first vane 21 may be larger than the size of the airfoil flow vortex formed by the first vane unit 231 and the second vane unit 232, to prevent the first vane 21 from interfering with the adjacent vane group 23, the included angle between two adjacent first vanes 21 in the two adjacent vane groups 23 may be slightly larger than the included angle between two first vanes 21 in the vane group 23, and exemplarily, the angle difference may be 0 ° to 5 °. That is, two first blades 21 form a fourth included angle γ, two adjacent first blades 21 in two adjacent blade groups 23 form a third included angle θ, and the third included angle θ is greater than or equal to the fourth included angle γ.

For a radial straight blade fan, the blades drive air to flow, the larger the area of the blades is, the larger the wind pressure generated by the blades is, and the larger the cooling wind flow is, but the larger the power consumption of the fan is, and correspondingly, the rotation impact noise of the blades and the air is large. The outer edge of the blade departing from the axis of the wheel disc 10 in this embodiment is provided with a notch 24, the notch 24 is concave towards one side of the axis of the wheel disc 10, and can be a strip-shaped notch or an arc-shaped notch, and the arc-shaped notch is smoothly connected with the wheel disc 10.

The blade is provided with the notch 24, so that the equivalent diameter of the blade can be reduced, namely the equivalent area of the blade is reduced, the wind pressure generated by the blade is reduced, the cooling wind flow is reduced, correspondingly, the power consumption of the fan is reduced, and the rotating impact noise of the blade and air is reduced.

Meanwhile, the size of the airflow vortex at the leeward side of the blade is reduced, the jet flow wake of the airflow vortex at the air outlet gap 40 disappears, namely, the unstable airflow at the air outlet gap 40 is replaced by the stable airfoil-shaped vortex airflow, the airflow speed at the air outlet gap 40 is uniformly distributed, and the vortex noise is reduced.

When the fan rotates, the air current probably flows out from the side edge that the blade deviates from the axis of the wheel disc 10, wherein, partial air current flows to the suction surface of the blade from the positive pressure surface of the blade through the side edge that the blade deviates from the wheel disc 10, and the partial air current can be driven repeatedly by the latter blade, and the energy consumption is high and the effective cooling air flow is low. The problem is not solved, the fan in the embodiment further comprises a front disc 30, the front disc 30 and the wheel disc 10 are coaxially arranged, and the plurality of blades are connected with the wheel disc 10 and the front disc 30; the front disc 30 is provided with an air inlet 31, and an air outlet gap 40 is formed between the edge of the front disc 30 and the edge of the wheel disc 10.

Specifically, the air inlet 31 penetrates the front disk 30 in the axial direction of the wheel disk 10, so that the front disk 30 is annular, and the width of the front disk 30 is adapted to the extension length of the blades in the radial direction. When the fan rotates, the air flow flows in from the air inlet 31 along the axial direction of the wheel disc 10, is driven by the blades and flows out from the air outlet gap 40 along the radial direction of the wheel disc 10, the front disc 30 prevents the air flow from flowing off through the edges of the side edges of the blades, the energy consumption is reduced, the cooling air flow is improved, and meanwhile, the fixing stability of the blades is improved.

The wheel disc 10 comprises a body 13 and an air outlet part 14, the body 13 is provided with a connecting part 131 connected with a motor, and blades are connected between the air outlet part 14 and the front disc 30; air-out portion 14 is the acute angle setting with front bezel 30 for air-out clearance 40 can be followed and is close to rim plate 10 axis one side and to deviating from rim plate 10 axis one side and reduce gradually, and air-out clearance 40 diminishes gradually, makes the air current can get into air-out clearance 40 with predetermineeing the angle, and the fan is given vent to anger evenly, prevents that air-out clearance 40 is too big, and the diffusion appears in the air current.

The size of the included angle between the air outlet portion 14 and the front disc 30 is based on the required fan pressure, and the larger the required fan pressure is, the larger the included angle can be.

Specifically, the air outlet portion 14 of the wheel disc 10 may be inclined toward one side of the front disc 30, or the front disc 30 may be inclined toward one side of the air outlet portion 14 as shown in this embodiment, so as to avoid the wheel disc 10 from being complex in structure and convenient to process and manufacture. The front plate 30 may be a flat plate or an arc plate having a certain curvature, and the arc plate may be an arc that is recessed toward the air outlet portion 14 side.

Further, the body 13 is provided with a connecting portion 131 connected with the motor, the connecting portion 131 can include a rotating shaft hole connected with the rotating shaft of the motor, and a plurality of bolt holes for fixing the rotating shaft and the body 13, the bolt holes are arranged at intervals along the rotating shaft of the motor, and the connection is reliable.

The body 13 further comprises a conical shell 132, the connecting portion 131 is located at the small end of the conical shell, the air outlet portion 14 extends from the edge of the large end of the conical shell to one side deviating from the axis of the wheel disc 10, the conical shell can be further arranged between the connecting portion 131 and the air outlet portion 14, and the size of the conical shell is gradually increased from one end of the connecting portion 131 to one end of the air outlet portion 14. The fan links to each other with the motor, and the fan communicates with the air-out pipeline, and is great when motor and air-out pipeline entry interval, can connect with the help of conical shell 132, and conical shell 132 sets up as required along the extension length of its self axis, and this embodiment does not restrict.

Example two

The present embodiment provides a motor, which includes a casing, a stator assembly, a rotor assembly, and the fan of the first embodiment, wherein the stator assembly and the rotor assembly are disposed in the casing, and the fan is connected to a rotating shaft of the rotor assembly.

Specifically, the motor can include the casing and the stator module and the rotor subassembly of holding in the casing, and the material of casing can be the metal, and intensity is high, and it can be split type including first casing and second casing, and first casing and second casing can pass through bolted connection, connect stably, set up the sealing washer between first casing and the second casing, and sealing performance is high.

Stator module and rotor subassembly relative rotation can generate electricity or for external load provides power, and stator module and rotor subassembly operation produce the heat, for making the heat in time give off, prevent that motor temperature is too high, and the motor can set up the fan, and the heat that the motor produced is taken away in the fan rotation. The fan can be connected with the non-load end of the rotating shaft in the rotor assembly, and the normal operation of the rotor assembly is not influenced. The structure, the working principle, the technical effect, and the like of the fan have been described in detail in the first embodiment, and are not described herein again.

The embodiments or implementation modes in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

In the description of the present specification, reference to the description of the terms "one embodiment", "some embodiments", "an illustrative embodiment", "an example", "a specific example", or "some examples", etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fan is characterized by comprising a wheel disc and a plurality of blades, wherein the wheel disc is connected with a motor; the blades protrude out of the wheel disc along the axial direction of the wheel disc, and the blades extend along the radial direction of the wheel disc;

the wheel disc has at least a first circumference and a second circumference, the radius of the first circumference is smaller than the radius of the second circumference; the plurality of blades comprise a plurality of first blades and a plurality of second blades, the plurality of first blades are arranged at intervals along the first circumference, the plurality of second blades are arranged at intervals along the second circumference, and the plurality of first blades and the plurality of second blades are arranged in a staggered manner along the circumferential direction of the wheel disc;

at least part of the windward side of the second blade corresponds to the first blade, and the second blade and the first blade form a blade unit.

2. The fan as claimed in claim 1, wherein the plurality of blades includes a blade group disposed at intervals in the circumferential direction, the blade group including one second blade and two first blades, the two first blades being disposed on both sides of the second blade;

the circumferential directions include a first circumferential direction and a second circumferential direction, the first circumferential direction and the second circumferential direction being opposite; in the first circumferential direction, the second blade and the first blade on the windward side thereof form a first blade unit, and in the second circumferential direction, the second blade and the other first blade form a second blade unit.

3. The fan as claimed in claim 2, wherein an end of the second blade adjacent to the first blade and an end of the first blade adjacent to the second blade are located on the same circumference.

4. The fan as claimed in claim 2, wherein one of the first blades forms a first angle with the second blade, and the other of the first blades forms a second angle with the second blade, and the first angle and the second angle are equal.

5. The fan as claimed in claim 2, wherein two of the first blades form a fourth angle, and two of the first blades adjacent to each other in two adjacent sets of the blades form a third angle, and the third angle is greater than or equal to the fourth angle.

6. The fan as claimed in any one of claims 1 to 5, wherein outer edges of the blades facing away from the wheel disk axis are notched.

7. The fan as claimed in any one of claims 1 to 5, further comprising a front disk, wherein the front disk and the wheel disk are coaxially disposed, and a plurality of the blades connect the wheel disk and the front disk;

the front disc is provided with an air inlet, and an air outlet gap is formed between the edge of the front disc and the edge of the wheel disc.

8. The fan as claimed in claim 7, wherein the wheel disc includes a body and an air outlet portion, the body is provided with a connection portion connected to a motor, and the blades are connected between the air outlet portion and the front disc;

the air outlet part and the front disc are arranged at an acute angle.

9. The fan as claimed in claim 8, wherein the body further includes a cone housing, the connecting portion is located at a small end of the cone housing, and the air outlet portion extends from a large end edge of the cone housing to a side away from the wheel disc axis.

10. An electrical machine comprising a housing, a stator assembly, a rotor assembly, and the fan of any of claims 1-9, the stator assembly and the rotor assembly being disposed within the housing, the fan being coupled to a shaft of the rotor assembly.