TW201835454A - Axial flow fan capable of increasing the wind pressure in a speed stalling zone of the axial flow fan so as to enhance the working performance of the fan - Google Patents

Abstract

An axial flow fan includes: a frame member having an inner wall, wherein a flow passage is formed by the inner wall of the frame member; a wind inlet and a wind outlet respectively provided at two opposite ends of the flow passage; a blade rotatably disposed in the flow passage and provided with a hub part and a plurality of blade parts connected to the hub part; a motor disposed in the hub part for driving the hub part to enable the blade to rotate along a rotation axis; and a plurality of ribs connected to the motor and the frame member, which is characterized in that: the inner wall is formed as a continuously curved surface, the flow passage is sequentially divided into a gradually-shrinking segment and a gradually-expanding segment from the wind inlet towards the wind outlet, and the axial length of the gradually-expanding segment is more than one time of that of the gradually-shrinking segment along the rotation axis. Accordingly, the wind pressure in a speed stalling zone of the axial flow fan can be increased so as to enhance the working performance of the fan.

Description

Axial fan

The invention relates to an axial flow fan, in particular to an axial flow fan whose flow path is a continuous curve from the air inlet to the air outlet to improve the performance of the fan.

According to the development of the electronics industry, the demand for heat dissipation of devices is increasing. At present, the most commonly used electronic heat sink is still a fan, and the axial fan is also a large one. The so-called axial fan is characterized in that the fan blade pushes air out in a direction parallel to the blade rotation axis. A common axial fan structure includes a frame body having an inner wall, the inner wall of the frame forming a first-class channel, and the fan blade is disposed in the flow channel, the blade has a hub portion and is distributed around the hub portion The blade has a motor inside to drive the hub portion to rotate the blade, and a plurality of ribs connect the motor and the frame.

However, the conventional fan structure shown in FIGS. 3 and 4 includes a frame 91 having an inner wall 911, and the inner wall 911 of the frame 91 forms a channel 912. A blade 92 is rotatably disposed within the flow passage 912. The blade 92 has a plurality of blade portions 921, each of the blade portions 921 having a blade leading edge 922, a blade trailing edge 923, and a blade tip 924. The distance between the tip 924 and the inner wall 911 is called the tip clearance.

The current axial fan still has the blade portion 921 rotating in the inner side of the flow passage 912, and the tip clearance interval from the leading edge 922 to the trailing edge 923 is different, so that the air does not flow smoothly in the tip clearance. The pressure inside the flow channel is unstable, and the airflow resistance is so great that the problem that the fan performance is difficult to be improved needs to be overcome.

The main object of the present invention is to provide an axial flow fan which can improve the working efficiency of the fan.

An axial flow fan according to the present invention includes a frame body having an inner wall, the inner wall of the frame forming a first-class track; the opposite ends of the flow channel are an air inlet and an air outlet respectively. a blade rotatably disposed in the flow channel, the blade having a hub portion and a plurality of blade portions connecting the hub portion; a motor disposed in the hub portion to drive the hub portion The fan blade is rotated according to a rotating shaft; the plurality of ribs are connected to the motor and the frame; and the inner wall is continuous curved surface from the air inlet to the air outlet; from the air inlet to the outlet The tuyere is sequentially divided into a tapered section and a diverging section, and the axial length of the diverging section along the rotating shaft is more than double that of the tapered section.

It is also possible that each of the blade portions is located only in the diverging section.

It is also possible that each of the blade portions has a blade leading edge, and the maximum radius of the blade leading edge is located at a position where the cross-sectional area is the smallest in the rotating section of the flow channel.

It is also possible that the tip clearance of each of the blades is at a fixed distance from the inner wall.

Thereby, the working efficiency of the axial flow fan can be improved.

In order to explain the technical features of the present invention in detail, the following preferred embodiments will be described with reference to the drawings, wherein:

As shown in Figures 1-2, a first embodiment of the present invention provides an axial fan 10. The axial fan 10 includes a frame 11, a blade 12, a motor 13, and a plurality of ribs 14.

The frame 11 has a first-class track 111 and an inner wall 112, and the inner wall 112 of the frame forms the flow path 111. The air passages 111 are respectively an air inlet 113 and an air outlet 114. The air is sucked into the flow passage 111 from the air inlet 113, and the air passage 111 is discharged from the air outlet 114.

The blade 12 is rotatably disposed in the flow path 111. The blade 12 has a hub portion 121 and a plurality of blade portions 122 connecting the hub portion 121, and further has a leaf on each of the blade portions 122. A leading edge 123, a trailing edge 124, a tip 125 and a blade root 126. It should also be noted that the gap between the portions of the tip 125 and the inner wall along the radial axis A is referred to herein as a tip clearance D.

The motor 13 is disposed in the hub portion 121 to drive the hub portion 121 such that the blade 12 rotates about a rotation axis A.

Each of the ribs 14 connects the motor 13 and the frame 11.

The axial flow fan 10 provided in this embodiment is characterized by:

The inner wall 112 has a continuous curved surface. By the same size of the tip clearance D of each part of the blade tip 125, the problem of uneven size of the tip tip of the prior art can be avoided, and air is reduced from the air inlet 113 to the During the process of the air outlet 114, too much air flow resistance is encountered, and the efficiency is improved.

In addition, starting from the air inlet 113 to the air outlet 114, the flow channel 111 is sequentially divided into a tapered section 115 and a diverging section 116, and the length LD of the diverging section 116 is the tapered section. 115 times longer than LC. The axial cross-sectional shape of the flow passage 111 is streamlined, and the purpose is to make the airflow pass through the flow passage 111 more gentle, in exchange for more wind pressure increase, thereby improving the performance.

In addition, in the present embodiment, the tip 125 is mainly located in the diverging section 116 of the flow path 111, and avoids the airflow resistance formed by the airflow near the tip edge 123 of the tip 125 being tapered by the flow path 111.

It is also possible that the leading edge 126 of each of the blade portions 122 intersects the blade tip 125 at a position in which the cross-sectional area is the smallest in the rotating section of the flow path 111. It is also possible that each of the tip clearances D is separated by a fixed distance, which reduces the various turbulence generated by the tip clearance D to improve the fan performance.

As can be seen from the above description, the axial flow fan 10 provided by the present invention can improve the working efficiency.

10‧‧‧Axial fan

11‧‧‧ frame

111‧‧‧ flow path

112‧‧‧ inner wall

113‧‧‧Air inlet

114‧‧‧air outlet

115‧‧‧ tapered section

116‧‧‧Expanded section

12‧‧‧ fan leaves

121‧‧‧Board body

122‧‧‧ Blade Department

123‧‧‧Leaf front

124‧‧‧leaf edge

125‧‧‧leaf

126‧‧‧ Ye Gen

13‧‧‧Motor

14‧‧‧ Ribs

A‧‧‧Rotary axis

D‧‧‧Leaf tip clearance

91‧‧‧ frame

911‧‧‧ inner wall

912‧‧‧ flow path

92‧‧‧ fan leaves

921‧‧‧ Blade Department

922‧‧‧leading edge

923‧‧‧Leaf edge

924‧‧‧ tip

Figure 1 is a perspective view of a first preferred embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing the first preferred embodiment of the present invention along the direction of the rotation axis. Figure 3 is a perspective view of a conventional fan. Figure 4 is a schematic cross-sectional view of a conventional fan.

Claims (4)

An axial flow fan includes a frame body having an inner wall, the inner wall of the frame forming a first-class channel; the opposite ends of the flow channel are respectively an air inlet and an air outlet; and a blade is rotatably disposed In the flow channel, the blade has a hub portion and a plurality of blade portions connecting the hub portion, each blade portion having a blade leading edge and a blade tip; and a motor disposed in the hub portion to drive the blade The hub portion rotates the blade according to a rotating shaft; the plurality of ribs connect the motor and the frame; wherein: the inner wall has a continuous curved surface; the air inlet starts from the air inlet to the air outlet, and the flow channel is sequentially Divided into a tapered section and a diverging section, the diverging section has an axial length that is more than double that of the tapered section. An axial flow fan according to claim 1, wherein: more than half of each of the blade portions is located in the diverging section. An axial flow fan according to claim 2, wherein: the tapered section and the diverging section interface naturally form a minimum area of the cross-sectional area in the rotating section of the flow passage; the front of each blade portion The intersection of the edge and the tip is at the minimum position of the cross-sectional area. The axial flow fan according to claim 1, wherein: a gap between the tip portions and the inner wall along the radial direction of the rotating shaft is a tip clearance, and a distance of the tip clearance of each of the blade portions is fixed.