Impeller and diagonal flow fan comprising same

Abstract

The invention discloses an impeller and a diagonal flow fan comprising the same. The impeller of the diagonal flow fan comprises a hub, a cylindrical part, a conical cover, a plurality of blades and a plurality of extension blades. The cylindrical part is connected with the hub and axially extends out of the bottom end of the hub. The conical cover is arranged around the hub. The blades are connected with the hub and the inner surface of the conical cover. The extending blades are arranged on the outer surface of the conical face cover and protrude out of the outer surface of the conical face cover.

Description

Technical Field

[0001] The present disclosure relates to an impeller and a diagonal flow fan including the impeller. Background Art

[0002] Cooling fans can generate airflow to dissipate heat more quickly. As technology advances, the computing power of electronic devices continues to increase, but the heat generated by electronic devices also increases. Therefore, mechanical engineers aim to design cooling fans with higher efficiency and lower noise. Summary of the invention

[0003] An embodiment of the present disclosure is to provide an impeller and a diagonal flow fan with improved efficiency and reduced noise.

[0004] According to some embodiments of the present disclosure, an impeller includes a hub, a cylindrical portion, a conical cover, a plurality of blades, and a plurality of extended blades. The cylindrical portion is connected to the hub and extends axially from the bottom end of the hub. The conical cover is arranged around the hub. The blades are connected to the hub and the inner surface of the conical cover. The extended blades are arranged on the outer surface of the conical cover and protrude from the outer surface of the conical cover.

[0005] In one or more embodiments of the present disclosure, the conical mask includes a first annular portion and a second annular portion, the first annular portion and the second annular portion are arranged on opposite sides of the conical mask. Each extension blade extends from the first annular portion to the second annular portion, and both ends of each extension blade are respectively connected to the first annular portion and the second annular portion.

[0006] In one or more embodiments of the present disclosure, the impeller includes an equal number of blades and extension blades, each of the extension blades being aligned with one of the blades.

[0007] In one or more embodiments of the present disclosure, the extension blade includes a first extension blade, and the blade includes a first blade aligned with the first extension blade. The first extension blade is an extension structure of the first blade.

[0008] In one or more embodiments of the present disclosure, the extending blade includes a first extending blade, the blade includes a first blade, and the first extending blade and the first blade have the same slope.

[0009] In one or more embodiments of the present disclosure, the blade and the extended blade are staggered.

[0010] In one or more embodiments of the present disclosure, the extending blade includes a first extending blade, and the blade includes a first blade. The first extending blade has the same slope as the first blade, and the first extending blade is offset relative to the first blade.

[0011] In one or more embodiments of the present disclosure, the impeller includes different numbers of blades and extended blades.

[0012] In one or more embodiments of the present disclosure, the extending blade includes a first extending blade, the blade includes a first blade, and the first extending blade and the first blade have different slopes.

[0013] In one or more embodiments of the present disclosure, the cone mask includes an annular portion, which is disposed at the bottom end of the cone mask and has a circular contour.

[0014] In one or more embodiments of the present disclosure, the conical mask includes an annular portion, which is disposed at the bottom end of the conical mask, and the contour line of the annular portion is formed by connecting a plurality of arcs.

[0015] According to some embodiments of the present disclosure, a diagonal flow fan includes a frame and an impeller. The frame has a containing space, an air inlet and an air outlet. The impeller is arranged in the containing space and is located between the air inlet and the air outlet. The impeller includes a hub, a cylindrical portion, a conical cover, a plurality of blades and a plurality of extended blades. The cylindrical portion is connected to the hub and extends axially from the bottom end of the hub. The conical cover is arranged around the hub. The blades are connected to the hub and the inner surface of the conical cover. The extended blades are arranged on the outer surface of the conical cover and protrude from the outer surface of the conical cover. A counterflow channel is formed between the conical cover and the inner surface of the frame, and the extended blades partially block the counterflow channel.

[0016] In one or more embodiments of the present disclosure, a first distance between the inner surface of the frame and the outer contour of each extending blade is a constant value.

[0017] In one or more embodiments of the present disclosure, the second distance between the bottom end of the conical mask and the inner surface of the frame is a constant, and the third distance between the top end of the conical mask and the inner surface of the frame is a constant. The first distance is equal to the second distance and equal to the third distance.

[0018] In one or more embodiments of the present disclosure, the frame includes a guide wall, which is disposed around the air inlet and extends toward the accommodating space. A fourth distance between the top of the conical mask and the guide wall is a constant value, and the fourth distance is equal to the first distance.

[0019] In one or more embodiments of the present disclosure, the inner surface of the frame has an arc-shaped area or a corner area facing the extended blade.

[0020] In summary, in the diagonal flow fan disclosed herein, one or more extended blades are disposed on the outer surface of the conical cover of the impeller, and the extended blades can block the counterflow airflow flowing through the gap between the impeller and the frame of the fan. Through the above configuration, the efficiency of the diagonal flow fan is improved, and the noise generated by the diagonal flow fan can be reduced.

[0021] It should be understood that the foregoing general description and the following detailed description are merely exemplary, and are intended to provide further explanation of the invention claimed in this case. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To make the above and other objects, features, advantages and implementations of the present disclosure more clearly understood, the accompanying drawings are described as follows:

[0023] Figure 1 A three-dimensional diagram showing a diagonal flow fan according to an embodiment of the present disclosure;

[0024] Figure 2 To show Figure 1 A perspective view of the diagonal flow fan shown from the opposite perspective;

[0025] Figure 3 To show the setting Figure 1 A perspective view of an impeller in a diagonal flow fan shown;

[0026] Figure 4 To show Figure 1 A cross-sectional view of the diagonal flow fan shown;

[0027] Figure 5 To show Figure 4 A magnified view of the BFC in the region;

[0028] Figure 6 To illustrate a pressure-flow diagram comparing the diagonal flow fan of the present disclosure and a conventional diagonal flow fan without extended blades;

[0029] Figure 7 To illustrate a noise-pressure diagram comparing the diagonal flow fan of the present disclosure and a conventional diagonal flow fan without extended blades;

[0030] Fig. 8A To show Figure 3 A side view of the impeller is shown;

[0031] Figure 8B To show Fig. 8A A top view of the impeller is shown;

[0032] Figure 8C To show Fig. 8A A cross-sectional view of the impeller shown;

[0033] Fig. 9A A side view showing an impeller according to another embodiment of the present disclosure;

[0034] Fig. 9B To show Fig. 9A A top view of the impeller is shown;

[0035] Fig. 9C To show Fig. 9AA cross-sectional view of the impeller shown;

[0036] Fig.10 A top view showing an impeller according to another embodiment of the present disclosure;

[0037] Fig.11 A perspective view showing an impeller according to another embodiment of the present disclosure;

[0038] Fig. 12A A side view showing an impeller according to another embodiment of the present disclosure;

[0039] Fig. 12B To show Fig. 12A A top view of the impeller is shown;

[0040] Fig.13 A partial cross-sectional view showing a diagonal flow fan according to another embodiment of the present disclosure; and

[0041] Fig.14 FIG. 1 is a cross-sectional view showing an impeller according to another embodiment of the present disclosure.

[0042] Description of Figure Numbers

[0043] 10,10A:Frame

[0044] 20: First frame

[0045] 22: Guide wall

[0046] 30: Second frame

[0047] 31:Plate body

[0048] 32: Base

[0049] 33: Static Leaf

[0050] 34: Axle tube

[0051] 40, 40A, 40B, 40C, 40D, 40E: Impeller

[0052] 41: Wheel hub

[0053] 42:Tubular part

[0054] 43: Cone mask

[0055] 43A: Inner surface

[0056] 43B: Outer surface

[0057] 43C: first annular portion

[0058] 43D: Second annular portion

[0059] 43E, 43F: Contour lines

[0060] 44:Leaf

[0061] 44A, 44B: side edges

[0062] 44C: Outer edge

[0063] 45:Balance hole

[0064] 49: Extended blade

[0065] 49A: First end

[0066] 49B: Second end

[0067] 70: Magnetic shell

[0068] 71: Magnet

[0069] 72: Shaft

[0070] 73: Bearing

[0071] 80: Winding

[0072] 81: Printed Circuit Board

[0073] 90: Countercurrent Channel

[0074] 91: Inhalation section

[0075] 92: Radial segment

[0076] 93: discharge section

[0077] 94:Bending section

[0078] 94A: Turning point

[0079] 100: Accommodation space

[0080] AF: Airflow

[0081] AG1: First angle

[0082] AG2: Second angle

[0083] AX: Central axis

[0084] BF: Countercurrent airflow

[0085] BFC: Area

[0086] C: Axial

[0087] D1, D2, D3, D4: distance

[0088] DF: Diagonal Flow Fan

[0089] DM1,DM2: diameter

[0090] G1: First diameter

[0091] G2: Second diameter

[0092] H1: First Height

[0093] H2: Second Height

[0094] IN: Air inlet

[0095] K1, L1: First position

[0096] K2, L2: Second position

[0097] OUT: Air outlet

[0098] W: Operation point DETAILED DESCRIPTION

[0099] The following is a detailed description of the embodiments of the present disclosure, examples of which are shown in the accompanying drawings. In the drawings and the specification, the same component symbols are used to represent the same or similar parts as much as possible. However, the specific structural and functional details disclosed herein are only used to describe exemplary embodiments, and therefore, may be implemented in a variety of alternative forms and should not be considered to be limited to the exemplary embodiments set forth herein. It should be understood that it is not intended to limit the exemplary embodiments to the specific forms disclosed, but rather to cover all modifications, equivalents and alternatives that fall within the scope of the present disclosure.

[0100] Please refer to Figure 1 . Figure 1 The present invention is a three-dimensional diagram showing a diagonal flow fan DF according to an embodiment of the present disclosure. The diagonal flow fan DF includes a frame 10 and an impeller 40. The frame 10 has a receiving space 100 and an air inlet IN connected to the receiving space 100. The air inlet IN is preferably circular. The impeller 40 is disposed in the receiving space 100 and faces the air inlet IN. When the impeller 40 rotates, air is introduced into the receiving space 100 through the air inlet IN. The frame 10 includes a guide wall 22, which is disposed around the air inlet IN and extends toward the receiving space 100. The guide wall 22 can guide the air to flow smoothly into the receiving space 100. The frame 10 includes a first frame 20 and a second frame 30 arranged along the axial direction C, and the first frame 20 and the second frame 30 are combined to form the receiving space 100. The first frame 20 may have the above-mentioned air inlet IN and the guide wall 22.

[0101] Please refer to Figure 2 . Figure 2 To show Figure 1The diagonal flow fan DF shown is a stereoscopic view viewed from the opposite perspective. The second frame 30 includes a plate 31, a base 32 and a plurality of stationary blades 33, and the plate 31, the base 32 and the stationary blades 33 form an air outlet OUT of the frame 10. The stationary blades 33 are arranged between the base 32 and the plate 31, and the two ends of each stationary blade 33 are respectively connected to the base 32 and the plate 31. When the impeller 40 rotates, air is introduced into the accommodating space 100 through the air inlet IN and discharged from the air outlet OUT.

[0102] Please refer to Figure 3 . Figure 3 To show the setting Figure 1 4 is a perspective view of an impeller 40 shown in FIG. The impeller 40 includes a hub 41, a cylindrical portion 42, a conical cover 43, a plurality of blades 44, and a plurality of balancing holes 45. The cylindrical portion 42 is connected to the hub 41 and extends axially from the bottom end of the hub 41. The conical cover 43 is disposed around the hub 41 and is concentrically disposed with the hub 41. The blades 44 are disposed around the hub 41. Each blade 44 has an inner edge connected to the hub 41 and an outer edge connected to the conical cover 43. Based on their connection relationship, the blades 44 can also be referred to as inner blades. Each blade 44 includes a three-dimensional curved surface. The balancing holes 45 are disposed on the top surface of the conical cover 43. The balancing holes 45 can be filled with balancing materials such as balancing soil to reduce vibrations occurring when the impeller 40 rotates.

[0103] like Figure 3 As shown, the impeller 40 further includes one or more extension blades 49 disposed on the conical cover 43. Specifically, the conical cover 43 has an inner surface 43A and an outer surface 43B opposite to the inner surface 43A, and the inner surface 43A and the outer surface 43B may have a curved appearance. The blade 44 is connected to the inner surface 43A of the conical cover 43, and the extension blade 49 is disposed on the outer surface 43B of the conical cover 43. In other words, the extension blade 49 is a raised structure formed on the outer surface 43B of the conical cover 43. In the present embodiment, the impeller 40 includes five extension blades 49 and five blades 44. As explained below, the extension blade 49 can help reduce the countercurrent airflow in the diagonal flow fan DF. The hub 41, the cylindrical portion 42, the conical cover 43, the blade 44 and the extension blade 49 can be an integrally formed structure and can be manufactured by injection molding.

[0104] Please refer to Figure 4 . Figure 4 To show Figure 1sectional view of the diagonal flow fan DF shown in FIG. The base 32 of the second frame 30 includes a shaft tube 34. The impeller 40 is driven by a motor, the motor includes a stator and a rotor, wherein the stator includes a winding 80 and a printed circuit board 81 (PCB) arranged around the shaft tube 34, and the rotor includes a magnetic shell 70, a magnet 71 and a rotating shaft 72. The magnetic shell 70 is arranged inside the cylindrical portion 42 of the impeller 40 and connected to the rotating shaft 72. The magnet 71 is arranged on the inner wall of the magnetic shell 70, and the position of the magnet 71 corresponds to the winding 80. The rotating shaft 72 is fixedly coupled to the hub 41 of the impeller 40. The rotating shaft 72 passes through the center of the magnetic shell 70 and extends into the shaft tube 34. The rotating shaft 72 is rotatably coupled to the shaft tube 34 via at least one bearing 73. The rotor and the stator are arranged between the impeller 40 and the second frame 30.

[0105] like Figure 4 As shown, the impeller 40 is located between the air inlet IN and the air outlet OUT. The top of the base 32 corresponds to the periphery of the cylindrical portion 42 in space. When the impeller 40 rotates, an air flow AF is formed that flows from the air inlet IN to the air outlet OUT. The air inlet IN and the air outlet OUT are arranged along the axial direction C. The air flow AF enters the diagonal flow fan DF from the air inlet IN, then passes through the gaps between the blades 44 of the impeller 40, then passes through the gaps between the stationary blades 33 of the second frame 30, and finally leaves the diagonal flow fan DF through the air outlet OUT. Preferably, the diameter DM2 of the air outlet OUT is larger than the diameter DM1 of the air inlet IN, and the contours of the conical cover 43 and the hub 41 expand radially. In this way, the air flow AF can gradually expand when passing through the impeller 40. The conical cover 43 extends obliquely, that is, the conical cover 43 is arranged obliquely to the axial direction C.

[0106] like Figure 4 As shown, there is a gap between the inner surface of the frame 10 and the conical cover 43 of the impeller 40. During the operation of the diagonal flow fan DF, most of the air flows along the path of the airflow AF, but a small amount of air leaks into the gap to form a counterflow airflow. The gap thus forms a counterflow channel 90.

[0107] Please refer to Figure 5 . Figure 5 To show Figure 4. The backflow channel 90 is preferably curved, or includes multiple non-parallel sections to change the direction of the airflow. In the present embodiment, the backflow channel 90 includes an intake section 91, a radial section 92, a discharge section 93, and a curved section 94. The conical mask 43 includes a first annular portion 43C and a second annular portion 43D, and the first annular portion 43C and the second annular portion 43D are arranged on opposite sides of the conical mask 43. The first annular portion 43C is arranged at the top of the conical mask 43 and is adjacent to the air inlet IN. The second annular portion 43D is arranged at the bottom of the conical mask 43 and is away from the air inlet IN. The intake section 91 is located between the second annular portion 43D of the conical mask 43 and the inner surface of the frame 10. The radial section 92 extends radially (in other words, the radial section 92 extends substantially perpendicular to the axial direction C), and the radial section 92 is located between the first annular portion 43C of the conical mask 43 and the inner surface of the frame 10. The discharge section 93 is located between the first annular portion 43C of the conical mask 43 and the guide wall 22. The inner surface of the frame 10 has an arc-shaped area, which faces the extended blades 49 and forms a curved section 94 between the suction section 91 and the radial section 92. The counterflow airflow BF flows along a first direction in the suction section 91 and flows along a second direction in the discharge section 93, which is opposite to the first direction, thereby increasing the flow resistance of the counterflow channel 90.

[0108] like Figure 5 As shown, the extended blades 49 of the impeller 40 protrude from the outer surface 43B of the conical cover 43 and partially block the curved section 94 of the counterflow channel 90. When the impeller 40 rotates, the extended blades 49 generate a pressure difference that can hinder the counterflow airflow BF. In addition, the extended blades 49 also cause the flow direction of the counterflow airflow BF to change suddenly, causing the counterflow airflow BF to lose energy. In this way, the counterflow airflow in the diagonal flow fan DF can be reduced, and the reduction of the counterflow airflow allows the diagonal flow fan DF to achieve higher efficiency and generate less noise.

[0109] like Figure 5As shown, the width of the suction section 91, the width of the radial section 92 and the width of the discharge section 93 are substantially constant. For example, the distance D1 between the second annular portion 43D of the conical cover 43 and the inner surface of the frame 10 can be a constant, the distance D2 between the end face of the first annular portion 43C of the conical cover 43 and the inner surface of the frame 10 can be a constant, and the distance D3 between the inner surface 43A of the conical cover 43 and the guide wall 22 can be a constant. In addition, the distance D4 between the outer contour line of the extended blade 49 and the inner surface of the frame 10 can be a constant. By keeping a fixed spacing between the impeller 40 and the frame 10, the pressure distribution can be made more regular, thereby improving the characteristics of the diagonal flow fan DF. The distances D1, D2, D3, and D4 are substantially equal. In order to effectively limit the countercurrent airflow, the distances D1, D2, D3, and D4 are less than or equal to 3 mm. In order to prevent the conical mask 43 from contacting the frame 10 (for example, slight vibration of the impeller 40 when rotating may cause this), the distances D1 , D2 , D3 , and D4 are at least 0.1 mm.

[0110] Please refer to Figure 6 . Figure 6 The following is a pressure-flow diagram comparing the diagonal flow fan DF disclosed herein and a conventional diagonal flow fan without extended blades. In the pressure-flow diagram, the vertical axis represents the wind pressure of the fan, and the horizontal axis represents the flow rate of the fan. Figure 6 As shown, the extended blades 49 enable the diagonal flow fan DF to reach the operating point W at a rotation speed of 9750 RPM. In contrast, the conventional fan without extended blades needs to reach the operating point W at a rotation speed of 10000 RPM. In other words, the diagonal flow fan DF can reach the operating point W at a rotation speed reduced by 2.5%. The efficiency improvement of the diagonal flow fan DF is attributed to the fact that the extended blades 49 can effectively reduce the reverse flow airflow.

[0111] Please refer to Figure 7 . Figure 7 The noise-pressure diagram is shown to compare the diagonal flow fan DF of the present disclosure with a conventional diagonal flow fan without extended blades. In the noise-pressure diagram, the vertical axis represents the noise of the fan, and the horizontal axis represents the wind pressure of the fan. Figure 7 As shown, the diagonal fan DF can achieve a noise reduction effect of up to 1.5 dBA compared to conventional fans. The noise reduction of the diagonal fan DF is attributed to the fact that the extended blades 49 can effectively reduce the reverse flow, and also to the fact that the diagonal fan DF with the extended blades 49 can operate at a lower speed as mentioned above.

[0112] Please refer to Fig. 8A . Fig. 8A To show Figure 34 is a side view of the impeller 40 shown in FIG. Each extended blade 49 of the impeller 40 extends from the first annular portion 43C of the conical cover 43 to the second annular portion 43D, and the two ends of each extended blade 49 are respectively connected to the first annular portion 43C and the second annular portion 43D. Through the above configuration, the impeller 40 can maintain a fixed spacing with the frame 10. The impeller 40 includes the same number of blades 44 and extended blades 49, and each extended blade 49 is aligned with one of the blades 44. For a pair of extended blades 49 and blades 44 aligned with each other, the first end 49A of the extended blade 49 intersects with the side edge 44A of the blade 44 at the second annular portion 43D of the conical cover 43. The second annular portion 43D has a circular contour line 43E. In other words, the thickness of the second annular portion 43D is a constant.

[0113] Please refer to Figure 8B . Figure 8B To show Fig. 8A 4 is a top view of the impeller 40 shown in FIG. The impeller 40 has a pair of extension blades 49 and a blade 44 aligned with each other. The second end 49B of the extension blade 49 intersects with the side edge 44B of the blade 44 at the first annular portion 43C of the conical cover 43. The second annular portion 43D has a circular contour line 43F. In other words, the diameter of the second annular portion 43D is a constant value.

[0114] Please refer to Figure 8C . Figure 8C To show Fig. 8A The cross-sectional view of the impeller 40 is shown. The vertical projection area of ​​the extended blade 49 of the impeller 40 on the conical cover 43 overlaps with the outer edge 44C of the blade 44. The extended blade 49 is equivalent to the extended structure of the blade 44 and protrudes from the outer surface 43B of the conical cover 43.

[0115] Please refer to Fig. 9A . Fig. 9A 1 is a side view of an impeller 40A according to another embodiment of the present disclosure. In this embodiment, the extension blade 49 is staggered with the blade 44. In other words, the blade 44 and the extension blade 49 are arranged in a non-aligned manner. At the second annular portion 43D of the conical cover 43 of the impeller 40A, the first end 49A of the extension blade 49 is offset relative to the side edge 44A of the blade 44.

[0116] Please refer to Fig. 9B . Fig. 9B To show Fig. 9A FIG. 4 is a top view of the impeller 40A. In the above-mentioned staggered arrangement, the second end 49B of the extended blade 49 of the impeller 40A adjacent to the first annular portion 43C is offset relative to the side edge 44B of the blade 44.

[0117] Please refer to Fig. 9C . Fig. 9CTo show Fig. 9A The vertical projection area of ​​the extended blade 49 of the impeller 40A on the conical cover 43 does not completely overlap with the outer edge 44C of the blade 44.

[0118] Please refer to Fig.10 . Fig.10 1 is a top view of an impeller 40B according to another embodiment of the present disclosure. The impeller 40B of this embodiment includes different numbers of extended blades 49 and blades 44. In the illustrated embodiment, the number of extended blades 49 of the impeller 40B is greater than the number of blades 44 (for example, the impeller 40B may include eight extended blades 49 and five blades 44). The extended blades 49 are symmetrically arranged about the central axis AX of the impeller 40B. In other embodiments, the number of extended blades 49 of the impeller 40B may be less than the number of blades 44, for example, the impeller 40B may include less than five extended blades 49.

[0119] Please refer to Fig.11 . Fig.11 FIG. 4 is a perspective view of an impeller 40C according to another embodiment of the present disclosure. In the impeller 40 of the aforementioned embodiment, the extended blades 49 and the blades 44 have the same slope. However, other configurations are also possible. Fig.11 As shown, there is a first angle AG1 between the extended blade 49 of the impeller 40C and the second annular portion 43D of the conical cover 43, and there is a second angle AG2 between the blade 44 of the impeller 40C and the second annular portion 43D of the conical cover 43. The first angle AG1 may be different from the second angle AG2, so that the extended blade 49 and the blade 44 have different slopes. The first angle AG1 may be any angle within the range of zero to ninety degrees.

[0120] Please refer to Fig. 12A . Fig. 12A A side view of an impeller 40D according to another embodiment of the present disclosure is shown. In this embodiment, the thickness of the second annular portion 43D of the conical cover 43 varies. For example, the second annular portion 43D may have a first contour line 43E formed by connecting a plurality of arcs. The first contour line 43E has a first height H1 at one or more first positions L1, and has a second height H2 at one or more second positions L2 different from the first position L1, and the second height H2 is different from the first height H1. In this embodiment, the second height H2 is greater than the first height H1. The first position L1 may be located at the lowest point of the arc, and the second position L2 may be located at the highest point of the arc. The extended blade 49 and the blade 44 may be connected to the second annular portion 43D from the first position L1, or the extended blade 49 and the blade 44 may be connected to the second annular portion 43D from other positions between the two second positions L2.

[0121] Please refer to Fig. 12B . Fig. 12B To show Fig. 12A 4 is a top view of the impeller 40D shown in FIG. The diameter of the second annular portion 43D of the conical cover 43 of the impeller 40D varies. For example, the second annular portion 43D may have a second contour line 43F formed by connecting a plurality of arcs. The second contour line 43F has a first diameter G1 at one or more first positions K1, and has a second diameter G2 at one or more second positions K2 different from the first position K1, and the second diameter G2 is different from the first diameter G1. In this embodiment, the first diameter G1 is greater than the second diameter G2. The first position K1 may be located at the outermost point of the arc, and the second position K2 may be located at the innermost point of the arc. The extension blade 49 and the blade 44 may connect the second annular portion 43D from the first position K1. Alternatively, the extension blade 49 and the blade 44 may also connect the second annular portion 43D from other positions between the two second positions K2. The first position K1 is the same position as the aforementioned first position L1. The second position K2 is the same position as the aforementioned second position L2.

[0122] Please refer to Fig.13 . Fig.13 Another embodiment in which the countercurrent channel has different shapes is shown. The countercurrent channel 90A of this embodiment includes an intake section 91, a radial section 92, a discharge section 93 and a transition section 94A. The conical mask 43 includes a first annular portion 43C and a second annular portion 43D, and the first annular portion 43C and the second annular portion 43D are arranged on opposite sides of the conical mask 43, wherein the first annular portion 43C is adjacent to the air inlet IN. The intake section 91 is located between the second annular portion 43D of the conical mask 43 and the inner surface of the frame 10A. The radial section 92 is located between the first annular portion 43C of the conical mask 43 and the inner surface of the frame 10A. The discharge section 93 is located between the first annular portion 43C of the conical mask 43 and the guide wall 22. The inner surface of the frame 10A has a corner area such as a right angle, and the corner area faces the extension blade 49 and forms a transition section 94A located between the intake section 91 and the radial section 92. The extended blades 49 of the impeller 40 protrude from the outer surface 43B of the conical cover 43 and extend toward the turning section 94A to block the reverse airflow BF.

[0123] like Fig.13As shown, the width of the suction section 91, the width of the radial section 92 and the width of the discharge section 93 are substantially constant. For example, the distance D1 between the second annular portion 43D of the conical cover 43 and the inner surface of the frame 10A can be a constant, the distance D2 between the end face of the first annular portion 43C of the conical cover 43 and the inner surface of the frame 10A can be a constant, and the distance D3 between the inner surface 43A of the conical cover 43 and the guide wall 22 can be a constant. In addition, the distance D4 between the outer contour line of the extended blade 49 and the inner surface of the frame 10A can be a constant. By keeping a fixed spacing between the impeller and the frame 10A, the pressure distribution can be made more regular, thereby improving the characteristics of the diagonal flow fan. The distances D1, D2, D3, and D4 are substantially equal. The distances D1, D2, D3, and D4 fall within the range of 0.1 mm to 3 mm.

[0124] Please refer to Fig.14 . Fig.14 1 is a cross-sectional view showing an impeller 40E according to another embodiment of the present disclosure. A difference between this embodiment and the aforementioned embodiment is that the inner surface 43A and the outer surface 43B of the conical cover 43 are substantially flat, and the inner surface 43A and the outer surface 43B extend obliquely (that is, the inner surface 43A and the outer surface 43B extend obliquely to (that is, not parallel to) the axial direction C). Another difference is that the balancing hole 45 for filling the balancing material has a variable aperture. Specifically, the diameter of the balancing hole 45 has a maximum value at its inlet and decreases along the axial direction C. The inner side of the balancing hole 45 is inclined and substantially parallel to the inner surface 43A of the conical cover 43.

[0125] In summary, in the diagonal flow fan disclosed herein, one or more extended blades are disposed on the outer surface of the conical cover of the impeller, and the extended blades can block the counterflow airflow flowing through the gap between the impeller and the frame of the fan. Through the above configuration, the efficiency of the diagonal flow fan is improved, and the noise generated by the diagonal flow fan can be reduced.

[0126] Although the present disclosure has been described in detail with reference to certain embodiments, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the embodiments described herein.

[0127] It is obvious to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the present disclosure. In view of this, the present disclosure is intended to cover modifications and variations that fall within the scope of the appended claims.

Claims

1. An impeller comprising: Wheel hub; A cylindrical portion connected to the hub and extending axially from a bottom end of the hub; A conical cover, arranged around the hub; A plurality of blades connected to the hub and the inner surface of the conical cover; as well as A plurality of extended blades are arranged on the outer surface of the conical mask and protrude from the outer surface of the conical mask. 2 . The impeller according to claim 1 , wherein the conical cover comprises a first annular portion, the first annular portion is disposed on one side of the conical cover, and each extended blade extends from the first annular portion to an outer surface of the conical cover.

3. The impeller according to claim 2, wherein the conical cover further includes a second annular portion, the second annular portion is arranged on the other opposite side of the conical cover, each extended blade extends from the first annular portion to the second annular portion, and both ends of each extended blade are respectively connected to the first annular portion and the second annular portion.

4. The impeller of claim 1, wherein the impeller comprises an equal number of the plurality of blades and the plurality of extension blades, each extension blade being aligned with one of the plurality of blades.

5. The impeller of claim 4, wherein the plurality of extended blades includes a first extended blade, the plurality of blades includes a first blade, the first blade is aligned with the first extended blade, wherein the first extended blade is an extension structure of the first blade.

6. The impeller of claim 1, wherein the plurality of extended blades include a first extended blade, the plurality of blades include a first blade, the first extended blade and the first blade having the same slope.

7. The impeller of claim 1, wherein the plurality of blades are offset from the plurality of extended blades.

8. The impeller of claim 7, wherein the plurality of extension blades includes a first extension blade, the plurality of blades includes a first blade, the first extension blade has the same slope as the first blade, and the first extension blade is offset relative to the first blade.

9. The impeller of claim 7, wherein the impeller comprises different numbers of the plurality of blades and the plurality of extended blades.

10. The impeller of claim 7, wherein the plurality of extended blades include a first extended blade, the plurality of blades include a first blade, the first extended blade and the first blade having different slopes. 11 . The impeller according to claim 1 , wherein the conical cover comprises an annular portion, the annular portion is disposed at a bottom end of the conical cover and has a circular contour. 12 . The impeller according to claim 1 , wherein the conical cover comprises an annular portion, the annular portion is disposed at the bottom end of the conical cover and has a contour line, and the contour line is formed by connecting a plurality of arc lines.

13. A diagonal flow fan, comprising: A frame body having a containing space, an air inlet and an air outlet; An impeller is disposed in the accommodating space and located between the air inlet and the air outlet, and the impeller comprises: Wheel hub; A cylindrical portion connected to the hub and extending axially from a bottom end of the hub; A conical cover, arranged around the hub; A plurality of blades connected to the hub and the inner surface of the conical cover; as well as A plurality of extended blades are arranged on the outer surface of the conical mask and protrude from the outer surface of the conical mask, wherein a countercurrent channel is formed between the conical mask and the inner surface of the frame, and the plurality of extended blades partially block the countercurrent channel. 14 . The diagonal flow fan according to claim 13 , wherein a first distance between the inner surface of the frame and an outer contour line of each extended blade is a constant value.

15. The diagonal flow fan according to claim 14, wherein a second distance between a bottom end of the conical cover and the inner surface of the frame is a constant, and a third distance between a top end of the conical cover and the inner surface of the frame is a constant, wherein the first distance is equal to the second distance and equal to the third distance.

16. The oblique flow fan according to claim 15, wherein the frame comprises a guide wall, the guide wall is arranged around the air inlet and extends toward the accommodating space, wherein a fourth distance between the top end of the conical cover and the guide wall is a constant, and the fourth distance is equal to the first distance. 17 . The diagonal flow fan according to claim 13 , wherein the inner surface of the frame has an arc region or a corner region facing the plurality of extended blades.

18. The diagonal flow fan according to claim 13, wherein the conical cover comprises a first annular portion and a second annular portion, the first annular portion and the second annular portion are arranged on opposite sides of the conical cover, wherein each extended blade extends from the first annular portion to the second annular portion, and both ends of each extended blade are respectively connected to the first annular portion and the second annular portion.

19. The diagonal flow fan according to claim 18, wherein the plurality of extended blades include a first extended blade, the plurality of blades include a first blade, the first blade is aligned with the first extended blade, and the first extended blade is an extended structure of the first blade. 20 . The diagonal flow fan according to claim 13 , wherein the plurality of extended blades include a first extended blade, the plurality of blades include a first blade, and the first extended blade and the first blade have the same slope.

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