CN112460065B

CN112460065B - Impeller and fan thereof

Info

Publication number: CN112460065B
Application number: CN202010914546.3A
Authority: CN
Inventors: 徐国栋; 张楯成; 杨朝富; 洪立翰
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2019-09-06
Filing date: 2020-09-03
Publication date: 2022-08-30
Anticipated expiration: 2040-09-03
Also published as: CN112460065A

Abstract

An impeller and a fan thereof are disclosed, wherein the impeller comprises a hub, a plurality of first blades, a plurality of second blades and a connecting piece. A plurality of first blades are arranged at intervals around the hub, wherein each first blade is connected with the periphery of the hub. A plurality of second blades are arranged around the hub at intervals, wherein each second blade is far away from the periphery of the hub and is positioned between two adjacent first blades. The connecting piece encircles the setting of wheel hub, and wears to establish a plurality of first blades and a plurality of second blade, and wherein the connecting piece does not contact with the blade edge of arbitrary side of each first blade, and the connecting piece does not contact with the blade edge of arbitrary side of each second blade.

Description

Impeller and fan thereof

Technical Field

The present invention relates to an impeller and a fan thereof, and more particularly, to an impeller and a fan thereof capable of achieving a target air volume and air pressure at a low rotation speed and reducing noise.

Background

As electronic devices are being developed to have high power and high density, the performance of electronic components used therein is also increasing. Generally, the performance of electronic components is enhanced, and the amount of heat generated is increased. If the heat is accumulated on the electronic component and cannot be removed properly, the electronic component will be damaged or destroyed due to the excessive heat, so that the electronic device cannot operate normally, and the reliability of the electronic device is affected. To solve the above problems, the conventional electronic device utilizes a fan as a heat dissipation device to remove heat from the inside of the electronic device.

At present, in order to improve the heat dissipation efficiency of the fan, a method of increasing the rotation speed of the fan is generally adopted to achieve the effect of increasing the wind pressure and the wind volume of the fan. However, when the rotation speed of the fan increases, the noise of the whole operation of the fan also increases.

Therefore, there is a need to develop an impeller and a fan thereof to solve the problems of the prior art.

Disclosure of Invention

The present invention provides an impeller and a fan thereof, wherein the fan can achieve a target air volume and a target air pressure at a low rotation speed by a special arrangement design of a plurality of main blades and a plurality of auxiliary blades, and the overall noise of the fan can be reduced.

To achieve the above objective, a preferred embodiment of the present invention provides an impeller, which includes a hub, a plurality of first blades, a plurality of second blades, and a connecting member. A plurality of first blades are spaced around the hub, wherein each first blade is connected to the periphery of the hub. A plurality of second blades are arranged around the hub at intervals, wherein each second blade is arranged far away from the periphery of the hub, and each second blade is positioned between two adjacent first blades. The connecting piece encircles the setting of wheel hub, and wears to establish a plurality of first blades and a plurality of second blade. Wherein the connecting member does not contact the blade edge of either side of each first blade and the connecting member does not contact the blade edge of either side of each second blade.

To achieve the above objective, another preferred embodiment of the present invention provides a fan, which includes a fan frame and an impeller. The fan frame is provided with a first surface, a second surface, a side wall, a first air inlet, an air outlet and a containing space. The first air inlet is positioned on the first surface, the second surface is opposite to the first surface, the air outlet is positioned between the first surface and the second surface, the first surface, the second surface and the side wall jointly define an accommodating space, and the first air inlet, the air outlet and the accommodating space are communicated. The impeller is arranged in the accommodating space of the fan frame and comprises a hub, a plurality of first blades, a plurality of second blades and a connecting piece. A plurality of first blades are spaced around the hub, wherein each first blade is connected to the periphery of the hub. The plurality of second blades are arranged around the hub at intervals, each second blade is far away from the periphery of the hub, each second blade is positioned between two adjacent first blades, part of each first blade is axially exposed in the axial projection surface of the first air inlet, and part of each second blade is axially exposed in the axial projection surface of the first air inlet. The connecting piece encircles the setting of wheel hub, and wears to establish a plurality of first blades and a plurality of second blade.

Drawings

Fig. 1A is a schematic structural view of an impeller according to a first embodiment of the present disclosure.

Fig. 1B is a side view of the impeller shown in fig. 1A.

Fig. 1C is a top view of the impeller shown in fig. 1A.

Fig. 2 is a partial structural top view of the impeller shown in fig. 1A.

Fig. 3 is a top view of an impeller according to a second embodiment of the present disclosure.

Fig. 4 is a top view of an impeller according to a third embodiment of the present disclosure.

Fig. 5A is a schematic structural diagram of a fan to which the impeller of the present disclosure is applied.

Fig. 5B is a top view of the fan of fig. 5A.

Fig. 5C is a bottom view of the fan of fig. 5A.

Detailed Description

Exemplary embodiments that embody features and advantages of this disclosure are described in detail below in the detailed description. It will be understood that the present disclosure is capable of various modifications without departing from the scope of the disclosure, and that the description and drawings are to be regarded as illustrative in nature, and not as restrictive.

Please refer to fig. 1A, which is a schematic structural diagram of an impeller according to a first embodiment of the present disclosure. As shown in the drawings, the impeller 1 is driven by a fan motor (not shown) to rotate in a counterclockwise direction, and includes a hub 2, a plurality of first blades 3, a plurality of second blades 4, and a connecting member 5. The first blades 3 constitute the main blades of the impeller 1 and are arranged around the hub 2 at intervals, and one end of each first blade 3 is connected to the periphery of the hub 2, wherein each first blade 3 may be, but not limited to, an arc-shaped piece. The plurality of second blades 4 constitute auxiliary blades of the impeller 1 and are arranged around the hub 2 at intervals, and each second blade 4 is arranged away from the periphery of the hub 2, i.e. each second blade 4 is not connected with the periphery of the hub 2, wherein each second blade 4 may be, but is not limited to, an arc-shaped blade. Each second blade 4 is located between two adjacent first blades 3. In one embodiment, the first blades 3 and the second blades 4 are sequentially arranged in a staggered manner and are disposed around the hub 2.

In the present embodiment, the hub 2 has a substantially cylindrical shape, and no other extension structure is connected to the first blade 3.

Referring to fig. 1B, a side view of the impeller shown in fig. 1A is shown. Referring to fig. 1A and 1B, the connecting member 5 of the impeller 1 is disposed around the hub 2 and connects the first blades 3 and the second blades 4. The connecting member 5 is a connecting ring, and connects the first blades 3 and the second blades 4 in a penetrating manner. In the present embodiment, the connection member 5 is inserted through the center of the blade surface of each first blade 3 without contacting the blade edge of either side of each first blade 3, and the connection member 5 is inserted through the center of the blade surface of each second blade 4 without contacting the blade edge of either side of each second blade 4.

Referring to fig. 1C, a top view of the impeller shown in fig. 1A is shown. Referring to fig. 1A and 1C, each first blade 3 includes a first blade surface 31, a second blade surface 32, and a connecting end 33. The first blade surface 31 and the second blade surface 32 of the first blade 3 are provided to face each other. In the present embodiment, the impeller 1 rotates in the counterclockwise direction, so the first blade surface 31 can be regarded as the windward surface of the first blade 3, and the second blade surface 32 can be regarded as the leeward surface of the first blade 3. The connecting member 5 of the impeller 1 is inserted into the center of the first blade surface 31 and the center of the second blade surface 32 of each first blade 3, so that each first blade 3 is connected with the connecting member 5. The first blade 3 is connected to the periphery of the hub 2 at a connecting end 33, and a part of the first blade 3 adjacent to the connecting end 33 (hereinafter referred to as a first part of the first blade 3) extends eccentrically in the radial direction from the periphery of the hub 2, and another part of the first blade 3 away from the connecting end 33 (hereinafter referred to as a second part of the first blade 3) extends eccentrically in the radial direction from the first part of the first blade 3. The first blades 3 are non-orthogonal to the periphery of the hub 2. In the present embodiment, a direction in which the second surface 32 of the first portion of the first blade 3 extends outward from the hub 2 is defined as a first direction, and a tangential direction (shown by a dotted line in fig. 1C) at a junction of the periphery of the hub 2 and the second surface 32 of the first portion of the first blade 3 is defined as a second direction. An included angle α is formed between the first direction and the second direction, wherein the included angle α is an acute angle. The first blade 3 further has a first leading edge 34, the first leading edge 34 is located at a connection position between the first blade surface 31 and the second blade surface 32, the first leading edge 34 is far away from the hub 2 relative to the connection end 33, and the first leading edge 34 is located on the outer periphery of the entire impeller 1.

Each second blade 4 includes a third blade surface 41, a fourth blade surface 42 and an inner end 43. The third blade surface 41 and the fourth blade surface 42 of the second blade 4 are provided to face each other. In the present embodiment, the impeller 1 rotates in a counterclockwise direction, so the third blade surface 41 can be regarded as the windward surface of the second blade 4, and the fourth blade surface 42 can be regarded as the leeward surface of the second blade 4. The connecting member 5 of the impeller 1 is inserted into the center of the third blade surface 41 and the center of the fourth blade surface 42 of each second blade 4, so that each second blade 4 is connected to the connecting member 5. The third surface 41 of the second blade 4 is disposed opposite to the second surface 32 of the adjacent first blade 3, the fourth surface 42 of the second blade 4 is disposed opposite to the first surface 31 of the other adjacent first blade 3, one side of the second blade 4 adjacent to the hub 2 is an inner end 43, and the inner end 43 of the second blade 4 is not connected to the periphery of the hub 2. In the present embodiment, the distance between the inner end 43 of each second blade 4 and the periphery of the hub 2 is the same. The second blade 4 has a second leading edge 44, the second leading edge 44 is located at the connection between the third blade surface 41 and the fourth blade surface 42, the second leading edge 44 is far from the hub 2 relative to the inner end 43, and the second leading edge 44 is located on the outer periphery of the entire impeller 1.

Please refer to fig. 2, which is a top view of a portion of the impeller shown in fig. 1A. As shown in the figure, the hub 2 has an axis O, a connection line between the first blade edge front end 34 of the nth first blade 3 of the plurality of first blades 3 and the axis O forms a first connection line L1, a connection line between the first blade edge front end 34 of the nth +1 first blade 3 of the plurality of first blades 3 and the axis O forms a second connection line L2, a connection line between the second blade edge front end 44 of the second blade 4 located between the nth first blade 3 and the nth +1 first blade 3 and the axis O forms a third connection line L3, wherein a first included angle θ 1 is formed between the first connection line L1 and the third connection line L3, a second included angle θ 2 is formed between the second connection line L2 and the third connection line L3, and the first included angle θ 1 is equal to the second included angle θ 2, where n is a natural number. In other embodiments, the first included angle θ 1 is not equal to the second included angle θ 2.

Please refer to fig. 3, which is a top view of an impeller according to a second embodiment of the present disclosure. As shown in the figure, the impeller 1a of the present embodiment includes a hub 2, a plurality of first blades 3, a plurality of second blades 4, and a connecting member 5. The structures and functions of the hub 2, the first blades 3, the second blades 4, and the connecting member 5 are partially similar to those of the hub 2, the first blades 3, the second blades 4, and the connecting member 5 shown in fig. 1C and 2, and therefore the same reference numerals are used to represent the structures and functions and they are not repeated herein. The present embodiment is different from the foregoing embodiments in that the angle between the plurality of first blades 3 and the plurality of second blades 4 of the impeller 1a is different from the angle between the plurality of first blades 3 and the plurality of second blades 4 of the impeller 1. In the present embodiment, a connection line between the first blade edge front end 34 of the nth first blade 3 of the plurality of first blades 3 and the shaft center O constitutes a first connection line L1, a connection line between the first blade edge front end 34 of the (n + 1) th first blade 3 of the plurality of first blades 3 and the shaft center O constitutes a second connection line L2, and a connection line between the first blade edge front end 34 of the (n + 2) th first blade 3 of the plurality of first blades 3 and the shaft center O constitutes a fourth connection line L4, wherein a third included angle θ 3 is formed between the first connection line L1 and the second connection line L2, a fourth included angle θ 4 is formed between the second connection line L2 and the fourth connection line L4, and the third included angle θ 3 is not equal to the fourth included angle θ 4, where n is a natural number.

Please refer to fig. 4, which is a top view of an impeller according to a third embodiment of the present disclosure. As shown in the figures, the impeller 1b of the present embodiment includes a hub 2, a plurality of first blades 3, a plurality of second blades 4, and a connecting member 5, wherein the structures and functions of the hub 2, the plurality of first blades 3, the plurality of second blades 4, and the connecting member 5 are partially similar to the structures and functions of the hub 2, the plurality of first blades 3, the plurality of second blades 4, and the connecting member 5 shown in fig. 1C and fig. 2, and therefore the same reference numerals are used to represent the structures and functions and they are not repeated herein. The present embodiment is different from the foregoing embodiments in that the angle between the plurality of first blades 3 and the plurality of second blades 4 of the impeller 1b is different from the angle between the plurality of first blades 3 and the plurality of second blades 4 of the impeller 1. In the present embodiment, a connecting line between the first edge tip 34 of the nth first blade 3 of the plurality of first blades 3 and the shaft center O constitutes a first connecting line L1, a connecting line between the first edge tip 34 of the (n + 1) th first blade 3 of the plurality of first blades 3 and the shaft center O constitutes a second connecting line L2, a connecting line between the second edge tip 44 of the mth second blade 4 located between the nth first blade 3 and the (n + 1) th first blade 3 and the shaft center O constitutes a third connecting line L3, wherein a first included angle theta 1 is formed between the first connecting line L1 and the third connecting line L3, a second included angle theta 2 is formed between the second connecting line L2 and the third connecting line L3, the first included angle θ 1 is not equal to the second included angle θ 2, and a resultant angle of the first included angle θ 1 and the second included angle θ 2 forms a first resultant angle θ 12, where n is a natural number and m is a natural number.

Referring to fig. 4, a connection line between the first blade edge front end 34 of the (n + 2) th first blade 3 of the plurality of first blades 3 and the shaft center O forms a fourth connection line L4, a connection line between the second blade edge front end 44 of the (m + 1) th second blade 4 located between the (n + 1) th first blade 3 and the (n + 2) th first blade 3 and the shaft center O forms a fifth connection line L5, wherein a fifth included angle θ 5 is formed between the second connection line L2 and the fifth connection line L5, a sixth included angle θ 6 is formed between the fifth connection line L5 and the fourth connection line L4, the fifth included angle θ 5 is not equal to the sixth included angle θ 6, and a resultant angle between the fifth included angle θ 5 and the sixth included angle θ 6 forms a second resultant angle θ 56, where n is a natural number and m is a natural number. In the present embodiment, the first resultant angle θ 12 is equal to the second resultant angle θ 56.

Please refer to fig. 5A and 5C, wherein fig. 5A is a schematic structural diagram of a fan with an impeller of the present disclosure, and fig. 5C is a bottom view of the fan in fig. 5A. Referring to fig. 5A and 5C, the fan 6 of the present disclosure includes a fan frame 7 and an impeller 1, wherein the

impellers

1, 1a, and 1b of the foregoing four embodiments can be applied to the fan 6 of the present disclosure, and therefore, the details are not repeated herein. The fan frame 7 has a first surface 71, a second surface 72, a sidewall 73, a first air inlet 711, an accommodating space 8, and an air outlet 81. First face 71 and second face 72 of fan frame 7 are disposed opposite to each other, and lateral wall 73 is located between first face 71 and second face 72, and one side of lateral wall 73 is connected and surrounds part of first face 71, and the other side of lateral wall 73 is connected and surrounds part of second face 72. The first air inlet 711 is located on the first surface 71 to serve as an inlet for a heat dissipating air flow. The first surface 71, the second surface 72 and the sidewall 73 together define an accommodating space 8, wherein the impeller 1 is disposed in the accommodating space 8. The air outlet 81 is located between the first surface 71 and the second surface 72 to serve as an outlet for the heat dissipation air flow, wherein the air outlet 81, the first air inlet 711 and the accommodating space 8 are communicated to form an air flow channel. In the present embodiment, the air outlet direction of the air outlet 81 and the air inlet direction of the first air inlet 711 are perpendicular to each other. In the present embodiment, the fan 6 further includes a fan motor (not shown), and the fan motor is connected to the impeller 1 and disposed in the accommodating space 8 of the fan frame 7. The fan motor of the fan 6 drives the impeller 1 to rotate, so that the heat dissipation airflow can be guided into the accommodating space 8 from the first air inlet 711, and the heat dissipation airflow is provided through the air outlet 81, thereby achieving active heat dissipation for electronic components inside the electronic device.

Please refer to fig. 5B, which is a top view of the fan shown in fig. 5A. Referring to fig. 5A and 5B, the impeller 1 is disposed in the accommodating space 8 of the fan frame 7, and the dotted line in fig. 5B indicates an outer periphery 11 of the impeller 1 as a whole. In the embodiment, the first air inlet 711 is substantially circular, but not limited thereto. The first air inlet 711 forms an axial projection plane as shown in fig. 5B. The hub 2, a portion of each first blade 3, and a portion of each second blade 4 are axially exposed in an axial projection plane of this first air inlet 711. Further, the inner end 43 of each second blade 4 may be exposed in the axial projection plane of the first air inlet 711. The connection piece 5 of the impeller 1 is substantially circular, but not limited thereto. The connection member 5 of the impeller 1 is shielded by the fan frame 7 and is not exposed in the axial projection plane of the first air inlet 711.

Referring to fig. 5A and 5C, the fan frame 7 further has a plurality of second air inlets 721, the plurality of second air inlets 721 are located on the second surface 72, wherein the plurality of second air inlets 721 are communicated with the first air inlets 711, the air outlet 81 and the accommodating space 8, the plurality of second air inlets 721 are used as another inlet of the heat dissipation air flow, an air inlet direction of each second air inlet 721 is perpendicular to an air outlet direction of the air outlet 81, and a rib of the fan frame 7 is formed between each second air inlet 721 and the adjacent second air inlet 721. In the present embodiment, the plurality of second air inlets 721 form a plurality of axial projection planes as shown in fig. 5C. A portion of each first blade 3 and a portion of each second blade 4 are axially exposed in a plurality of axial projection planes of this second air inlet 721. Further, the inner end 43 of each second vane 4 may be exposed to the axial projection surfaces of the second air inlets 721, and the connecting member 5 of the impeller 1 is shielded by the fan frame 7 and cannot be exposed to the axial projection surfaces of the second air inlets 721. Preferably, the fan 6 has two air inlets and a single air outlet, and the air is axially introduced from the fan 6 and radially discharged from the fan 6, so as to effectively increase the air volume and the air pressure of the fan 6.

In summary, the present disclosure provides an impeller and a fan thereof, which can achieve a target air volume and air pressure at a low rotation speed and reduce the overall noise of the fan by a special arrangement design of a plurality of main blades and a plurality of auxiliary blades, such as staggered arrangement between the plurality of main blades and the plurality of auxiliary blades.

Description of the symbols

1. 1a, 1 b: impeller

11: outer periphery of impeller

2: wheel hub

3: first blade

31: first leaf surface

32: second blade surface

33: connecting end

34: first leading edge

4: second blade

41: third leaf noodle

42: the fourth leaf surface

43: inner side end

44: second leading edge

5: connecting piece

6: fan with cooling device

7: fan frame

71: first side

711: first air inlet

72: second surface

721: second air inlet

73: side wall

8: containing space

81: air outlet

α: included angle

L1: first connecting wire

L2: second connecting line

L3: third connecting line

L4: the fourth connecting line

L5: the fifth connecting line

θ 1: first included angle

θ 2: second included angle

θ 3: third included angle

θ 4: fourth angle

θ 12: first closed angle

θ 56: second closed angle

θ 5: fifth angle

θ 6: sixth angle

O: axial center

Claims

1. An impeller, comprising:

a hub;

a plurality of first blades arranged at intervals around the hub, wherein each first blade is connected with one periphery of the hub;

a plurality of second blades arranged around the hub at intervals, wherein each second blade is arranged far away from the periphery of the hub, and each second blade is positioned between two adjacent first blades; and

the connecting piece is arranged around the hub and penetrates through the first blades and the second blades, wherein the connecting piece is not contacted with the blade edge of any side of each first blade, and the connecting piece is not contacted with the blade edge of any side of each second blade;

each first blade comprises a first blade surface, a second blade surface, a connecting end and a first blade edge front end, the first blade surface and the second blade surface are arranged oppositely, the connecting piece penetrates through the center of the first blade surface and the center of the second blade surface of each first blade and is not contacted with the blade edge of any side of each first blade and the second blade, the connecting end is arranged at the connecting position of the periphery of the hub, the first blade edge front end is positioned at the connecting position of the first blade surface and the second blade surface, and the first blade edge front end is far away from the hub relative to the connecting end;

the hub has an axis, the first blade edge front end of the nth first blade among the plurality of first blades and the connecting line of the axis form a first connecting line, the first blade edge front end of the (n + 1) th first blade and the connecting line of the axis form a second connecting line, the first blade edge front end of the (n + 2) th first blade and the connecting line of the axis form a fourth connecting line, wherein a third included angle is formed between the first connecting line and the second connecting line, a fourth included angle is formed between the second connecting line and the fourth connecting line, and the third included angle is not equal to the fourth included angle.

2. The impeller as claimed in claim 1, wherein each of the second blades includes a third blade surface, a fourth blade surface, an inner side end and a second blade edge front end, the third blade surface and the fourth blade surface are disposed opposite to each other, the connecting member is disposed through a center of the third blade surface and a center of the fourth blade surface of each of the second blades, one side of the second blade adjacent to the hub is the inner side end, the inner side end is not connected to the periphery of the hub, the second blade edge front end is located at a connection between the third blade surface and the fourth blade surface, and the second blade edge front end is away from the hub relative to the inner side end.

3. The impeller of claim 2, wherein the distance between the inner end of each of the second blades and the periphery of the hub is the same.

4. The impeller as claimed in claim 2, wherein a connecting line between the leading end of the first blade edge of the nth first blade among the plurality of first blades and the shaft center forms a first connecting line, a connecting line between the leading end of the first blade edge of the (n + 1) th first blade and the shaft center forms a second connecting line, and a connecting line between the leading end of the second blade edge of the nth first blade and the (n + 1) th first blade and the shaft center forms a third connecting line, wherein the first connecting line and the third connecting line form a first included angle, the second connecting line and the third connecting line form a second included angle, and the first included angle is equal to the second included angle.

5. The impeller as claimed in claim 2, wherein a connecting line between the leading end of the first blade edge of the nth first blade of the plurality of first blades and the shaft constitutes a first connecting line, a connecting line between the leading end of the first blade edge of the (n + 1) th first blade and the shaft constitutes a second connecting line, and a connecting line between the leading end of the second blade edge of the second blade located between the nth first blade and the (n + 1) th first blade and the shaft constitutes a third connecting line, wherein the first connecting line and the third connecting line form a first angle, the second connecting line and the third connecting line form a second angle, and the first angle is not equal to the second angle.

6. The impeller as claimed in claim 2, wherein a connecting line between the first leading edge of the nth first blade of the plurality of first blades and the shaft constitutes a first connecting line, a connecting line between the first leading edge of the n +1 th first blade and the shaft constitutes a second connecting line, and a connecting line between the first leading edge of the n +2 th first blade and the shaft constitutes a fourth connecting line, wherein a first closed angle is formed between the first connecting line and the second connecting line, a second closed angle is formed between the second connecting line and the fourth connecting line, and the first closed angle is equal to the second closed angle.

7. The impeller as claimed in claim 6, wherein a connecting line between the leading end of the second blade edge of the mth second blade located between the nth first blade and the (n + 1) th first blade and the shaft forms a third connecting line, the third connecting line forms a first included angle with the first connecting line, the third connecting line forms a second included angle with the second connecting line, and the first included angle is not equal to the second included angle.

8. A fan, comprising:

the fan frame is provided with a first surface, a second surface, a side wall, a first air inlet, an air outlet and a containing space, wherein the first air inlet is positioned on the first surface, the first surface is opposite to the second surface, the air outlet is positioned between the first surface and the second surface, the first surface, the second surface and the side wall jointly define the containing space, and the first air inlet, the air outlet and the containing space are communicated; and

an impeller, set up in this accommodation space, and contain:

a hub;

a plurality of first blades arranged around the hub at intervals, wherein each first blade is connected with one periphery of the hub;

a plurality of second blades, which are spaced around the hub, wherein each second blade is disposed away from the periphery of the hub, and each second blade is located between two adjacent first blades, wherein a portion of each first blade is axially exposed in an axial projection plane of the first air inlet, and a portion of each second blade is axially exposed in the axial projection plane of the first air inlet; and

a connecting piece which is arranged around the hub and penetrates through the plurality of first blades and the plurality of second blades;

9. The fan as claimed in claim 8, wherein the connection member does not contact with the blade edge of either side of each of the first blades, and the connection member does not contact with the blade edge of either side of each of the second blades.

10. The fan of claim 8, wherein the connector is not exposed in the axial projection plane of the first air inlet.

11. The fan as claimed in claim 8, wherein the fan further comprises at least one second air inlet located on the second surface, and the connecting member is not exposed to the axial projection surface of the at least one second air inlet.

12. The fan as claimed in claim 8, wherein each of the first blades includes a first blade surface, a second blade surface, a connecting end and a first blade edge front end, the first blade surface and the second blade surface are disposed opposite to each other, the connecting member is disposed through a center of the first blade surface and a center of the second blade surface of each of the first blades, the connecting end is located at a position where the first blade is connected to the periphery of the hub, the first blade edge front end is located at a position where the first blade surface is connected to the second blade surface, and the first blade edge front end is away from the hub relative to the connecting end.

13. The fan as claimed in claim 12, wherein each of the second blades includes a third blade surface, a fourth blade surface, an inner end and a second blade edge front end, the third blade surface and the fourth blade surface are disposed opposite to each other, the connecting member is disposed through a center of the third blade surface and a center of the fourth blade surface of each of the second blades, one side of the second blade adjacent to the hub is the inner end, the inner end is not connected to the periphery of the hub, the inner end of the second blade is exposed to the projection plane of the first air inlet, the second blade edge front end is located at a connection between the third blade surface and the fourth blade surface, and the second blade edge front end is away from the hub relative to the inner end.

14. The fan as claimed in claim 13, wherein a connecting line between the leading end of the first blade edge of the nth first blade among the plurality of first blades and the shaft constitutes a first connecting line, a connecting line between the leading end of the first blade edge of the (n + 1) th first blade and the shaft constitutes a second connecting line, and a connecting line between the leading end of the second blade edge of the nth first blade and the (n + 1) th first blade and the shaft constitutes a third connecting line, wherein the first connecting line and the third connecting line form a first included angle, the second connecting line and the third connecting line form a second included angle, and the first included angle is equal to the second included angle.

15. The fan as claimed in claim 13, wherein a connecting line between the leading end of the first blade edge of the nth first blade of the plurality of first blades and the shaft constitutes a first connecting line, a connecting line between the leading end of the first blade edge of the (n + 1) th first blade and the shaft constitutes a second connecting line, and a connecting line between the leading end of the second blade edge of the second blade located between the nth first blade and the (n + 1) th first blade and the shaft constitutes a third connecting line, wherein the first connecting line and the third connecting line form a first angle, the second connecting line and the third connecting line form a second angle, and the first angle is not equal to the second angle.

16. The fan as claimed in claim 13, wherein a connecting line between the first blade edge front end of the nth first blade of the plurality of first blades and the shaft constitutes a first connecting line, a connecting line between the first blade edge front end of the (n + 1) th first blade and the shaft constitutes a second connecting line, and a connecting line between the first blade edge front end of the (n + 2) th first blade and the shaft constitutes a fourth connecting line, wherein a third included angle is formed between the first connecting line and the second connecting line, a fourth included angle is formed between the second connecting line and the fourth connecting line, and the third included angle is not equal to the fourth included angle.

17. The fan as claimed in claim 13, wherein a connecting line between the leading end of the first edge of the nth first blade of the plurality of first blades and the shaft constitutes a first connecting line, a connecting line between the leading end of the first edge of the n +1 th first blade and the shaft constitutes a second connecting line, and a connecting line between the leading end of the first edge of the n +2 th first blade and the shaft constitutes a fourth connecting line, wherein a first resultant angle is formed between the first connecting line and the second connecting line, a second resultant angle is formed between the second connecting line and the fourth connecting line, and the first resultant angle is equal to the second resultant angle.

18. The fan as claimed in claim 17, wherein a connecting line between the front end of the second blade edge of the mth second blade and the (n + 1) th first blade and the shaft forms a third connecting line, the third connecting line and the first connecting line form a first included angle, the third connecting line and the second connecting line form a second included angle, and the first included angle is not equal to the second included angle.