WO2020077802A1 - Contra-rotating fan - Google Patents

Abstract

A contra-rotating fan (1), comprising a first-stage impeller (10) and a second-stage impeller (20) that have opposite rotation directions. The first-stage impeller (10) is located at an air inlet side of the contra-rotating fan (1), and the second-stage impeller (20) is located at an air outlet side of the contra-rotating fan (1). The first-stage impeller (10) comprises a plurality of first blades (110) distributed along the circumferential direction thereof, and the second-stage impeller (20) comprises a plurality of second blades (210) distributed along the circumferential direction thereof. The axial width of the first blades (110) is greater than the axial width of the second blades (210). The present contra-rotating fan may not only guarantee that the air outlet direction remains axial, but may also increase outputted wind pressure and wind volume.

Description

Counter-rotating fan

Cross-reference of related applications

This application is based on the Chinese patent application with the application number 201811198972.0, the application date is October 15, 2018 and the Chinese patent application with the application number 201821672645.X and the application date is October 15, 2018, and requires the above-mentioned Chinese patent application Priority, the entire content of the aforementioned Chinese patent application is hereby incorporated by reference.

Technical field

The invention relates to the technical field of fans, in particular to a counter-rotating fan.

Background technique

The counter-rotating electric fan is a new type of electric fan, which has the characteristics of low noise, long air supply distance and controllable air type. Existing counter-rotating electric fans generally have the same axial width of the two-stage fan blades and rotate in opposite directions. The swirling airflow at the outlet of the first-stage fan blade can be derotated by the second-stage fan blade, thereby achieving the functions of straight wind, long-distance air supply, and accelerated air circulation.

When the two-stage rotation speed is different, the two-stage fan can do not race or even disperse the airflow, thereby achieving a wide dispersion of wind, making the human body feel very soft in the vicinity. However, the size of the fan in home appliances is often limited by the structure. For the axial width, how to allocate the limited axial width to the two-stage fan blade is a problem worthy of study. In the existing counter-rotating electric fan, the axial width of the two-stage fan blades is equal. For the counter-rotating second-stage blade, the airflow at the outlet of the first-stage blade is equivalent to providing reverse pre-rotation. In designs that require high wind pressure, due to the need to provide higher wind pressure, the two-stage fan blade load is very high, resulting in a large turning angle of the second-stage blade shape, unable to achieve axial airflow, making the outlet airflow It also has the speed component of the second-stage fan blade rotation, making the air supply distance closer.

Summary of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a counter-rotating fan, which has a relatively long blowing distance.

A counter-rotating fan according to an embodiment of the present invention includes a first-stage impeller and a second-stage impeller having opposite rotation directions, the first-stage impeller is located on the air inlet side of the counter-rotating fan, and the second-stage impeller is located on the On the outlet side of the counter-rotating fan, the first-stage impeller includes a plurality of first blades distributed along its circumferential direction, and the second-stage impeller includes a plurality of second blades distributed along its circumferential direction, the first The axial width of one blade is larger than the axial width of the second blade.

According to the counter-rotating fan of the embodiment of the present invention, since the axial width of the first blade is larger than the axial width of the second blade, it can not only ensure that the wind direction of the counter-rotating fan remains axial, but also increase the wind output from the counter-rotating fan Pressure and air volume.

According to an embodiment of the present invention, the axial width of the first blade is A1, and the axial width of the second blade is A2, and A2 does not exceed twice A1.

According to an embodiment of the present invention, the axial width A1 of the first blade ranges from 25 mm to 55 mm, and the axial width A2 of the second blade ranges from 25 mm to 55 mm.

According to an embodiment of the present invention, each edge of each of the first blades in the circumferential direction is respectively a first leading edge and a first trailing edge, and the first leading edge and the first trailing edge are both radially formed by Bending in the direction of rotation from the inside to the outside, and the bending protrusion of the first leading edge is directed to the first trailing edge corresponding to the first blade; each of the second blades is circumferentially edged on both sides Are a second leading edge and a second trailing edge, respectively, the second leading edge and the second trailing edge are both curved toward the direction of rotation in a radial direction from inside to outside, and the bending of the second leading edge is convex The outgoing point corresponds to the second trailing edge on the second blade.

According to an embodiment of the present invention, the leading edge bending angle Γ _le of the first blade and the second blade ranges from 15 ° to 75 °; wherein, the projection of the first leading edge on the radial cross section is A first leading edge line, the angle between the tangent line and the radial line at any point on the first leading edge line is the leading edge bending angle of the first blade; the second leading edge is in a radial section The projection is the second leading edge line, the angle between the tangent line and the radial line at any point on the second leading edge line is the leading edge bending angle of the second blade, and the radial cross section is perpendicular to the In the plane of the rotation axis of the counter-rotating fan, the radial line is a straight line passing through the rotation axis in the radial section.

According to an embodiment of the present invention, the trailing edge bending angle Γ _te of the first blade and the second blade ranges from 0 ° to 60 °; wherein, the projection of the first trailing edge on the radial section is A first trailing edge line, the angle between the tangent line and the radial line at any point on the first trailing edge line is the trailing edge bending angle of the first blade; The projection is the second trailing edge line, and the angle between the tangent line and the radial line at any point on the second trailing edge line is the trailing angle of the second blade; the radial section is perpendicular to the In the plane of the rotation axis of the counter-rotating fan, the radial line is a straight line passing through the rotation axis in the radial section.

According to an embodiment of the present invention, the number of the first blades is not equal to the number of the second blades.

According to an embodiment of the present invention, the counter-rotating fan further includes: an enclosure and two net enclosures, the net enclosure surrounds the outer peripheral sides of the first-stage impeller and the second-stage impeller, two The net cover is connected to opposite sides of the enclosure.

According to a specific embodiment of the present invention, the enclosure includes: a ring rib and a plurality of horizontal ribs, the ring ribs are formed into a ring shape, a plurality of the horizontal ribs are respectively connected to the ring ribs, and two of each horizontal rib The ends are respectively connected to the two net covers.

According to an embodiment of the present invention, the counter-rotating fan further includes: a post, the post is connected below the enclosure.

Additional aspects and advantages of the present invention will be partially given in the following description, and some will become apparent from the following description, or be learned through the practice of the present invention.

BRIEF DESCRIPTION

The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

FIG. 1 is an overall structural diagram of a counter-rotating fan according to an embodiment of the present invention.

2 is a schematic structural diagram of a first-stage impeller according to an embodiment of the present invention.

3 is a schematic structural diagram of a second-stage impeller according to an embodiment of the present invention.

FIG. 4 is a vector diagram of airflow on the inlet side of the first-stage impeller according to an embodiment of the present invention.

5 is an airflow vector diagram of the first-stage impeller outlet side and the second-stage impeller inlet side of the embodiment of the present invention.

FIG. 6 is a vector diagram of airflow on the air outlet side of the second-stage impeller according to an embodiment of the present invention.

7 is a fan relationship diagram of the ratio between the axial width A1 of the first blade and the axial width A2 of the second blade and the output of the counter-rotating fan in the embodiment of the present invention.

8 is a schematic structural view of a first-stage impeller and a second-stage wheel according to an embodiment of the present invention.

Reference mark:

Counter-rotating fan 1,

The first stage impeller 10, the first blade 110,

The second stage impeller 20, the second blade 210,

Enclosure 30,

Net cover 40,

The first leading edge Le1, the first trailing edge Te1, the radial line Ld,

The second leading edge Le2 and the second trailing edge Te2.

detailed description

Hereinafter, embodiments of the present invention will be described in detail. Examples of the embodiments are shown in the drawings, in which the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention, and cannot be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, only for convenience The present invention is described and the description simplified, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be construed as limiting the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise stated, "plurality" means two or more.

In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be fixed connection or detachable Connected, or connected integrally; either mechanically or electrically; directly connected, or indirectly connected through an intermediary, or internally connected between two components. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood in specific situations.

The counter-rotating fan 1 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

As shown in FIGS. 1-3, the counter-rotating fan 1 according to an embodiment of the present invention includes a first-stage impeller 10 and a second-stage impeller 20 having opposite rotation directions. The first-stage impeller 10 is located on the air inlet side of the counter-rotating fan 1 The second-stage impeller 20 is located on the outlet side of the counter-rotating fan 1, the first-stage impeller 10 includes a plurality of first blades 110 distributed along its circumferential direction, and the second-stage impeller 20 includes a plurality of first blades distributed along its circumferential direction For the two blades 210, the axial width of the first blade 110 is greater than the axial width of the second blade 210.

The counter-rotating fan 1 of the embodiment of the present invention can be applied to electric fans, circulation fans, ventilation fans, air-conditioning fans, and other devices that need to send out air. The counter-rotating fan 1 of the embodiment of the present invention is mainly used to promote air flow rather than heat exchange.

First of all, it should be noted that the rotation speed of the first blade 110 and the rotation speed of the second blade 210 can affect the entire blower distance of the counter-rotating fan 1, but the main blades discussed in this application are the first blade 110 and the second blade 210 The relationship between the axial width and the blowing distance of the counter-rotating fan 1. Therefore, the following analysis process is based on the premise that the rotation speeds of the first blade 110 and the second blade 210 are unchanged. In addition, the axial width of the first blade 110 refers to the width shown in A1 in FIG. 8, and the axial width of the second blade 210 refers to the width shown in A2 in FIG. 8.

It should be added that, as shown in FIGS. 4-6, U1 is the rotational linear velocity of the first-stage impeller 10, W1 is the airflow velocity of the first-stage impeller 10 in the rotating coordinate system, and the vector synthesis of U1 and W1 The result is V1, which represents the airflow velocity of the first-stage impeller 10 felt by the human body. W2 is the airflow velocity of the first-stage impeller 10 in the rotating coordinate system. The vector synthesis result of U1 and W2 is V2, and V2 represents the airflow velocity of the first-stage impeller 10 felt by the human body. W3 is the airflow velocity of the second-stage impeller 20 in the rotating coordinate system, and U2 is the rotational linear velocity of the second-stage impeller 20. Since the first-stage impeller 10 is located on the air inlet side of the second-stage impeller 20 and the rotation directions of the first-stage impeller 10 and the second-stage impeller 20 are opposite, V2 = -V3, and V3 represents the second Inlet airflow speed of the stage impeller 20. W4 is the airflow velocity of the second-stage impeller 20 in the rotating coordinate system. The vector synthesis result of U2 and W4 is V4. V4 represents the airflow velocity of the second-stage impeller 20 felt by the human body. When V4 and the shaft The smaller the angle of the directional vector Vax, the closer the V4 is to the axial direction, that is, the closer the air outlet direction of the second-stage impeller 20 is to the axial direction, thereby achieving the purpose of a longer air outlet distance of the counter-rotating fan 1.

It can be understood that since V4 is synthesized by W4 and U2, U2 is the rotational linear velocity of the second-stage impeller 20 and U2 is a fixed value according to the foregoing description. Therefore, in order to ensure the axial direction of V4 (that is, V4 coincides with Vax as much as possible), at this time, we can think that the direction of W4 is limited.

However, in some occasions, the counter-rotating fan 1 needs to output a large wind pressure, so it is necessary to increase the airflow turning angle of the second blade 210 (that is, the angle difference between W3 and W4), while increasing the airflow turning angle of the second blade 210 has Two methods:

(1) Increase the thickness of the second blade 210, so that although the airflow turning angle of the second blade 210 is increased, the direction of W3 and W4 will be changed, especially W4 will be more biased to the opposite direction of U2, then The airflow velocity V4 of the second-stage impeller 20 will have a tangential component, which will cause the outlet airflow of the second-stage impeller 20 to spin, that is, the wind direction of the second-stage impeller 20 deviates from the axial direction, thereby making the counter-rotating The blowing distance of the fan 1 is not far. Therefore, increasing the thickness of the second blade 210 can only guarantee one of the axial direction of the outlet air flow and the output wind pressure, that is, increasing the second blade 210 can ensure the output wind pressure of the counter-rotating fan 1, but it will cause The wind direction of the rotary fan 1 deviates from the axial direction, thereby reducing the air supply distance of the rotary fan 1; reducing the second blade 210 can certainly ensure that the wind direction of the rotary fan 1 is as close to the axial direction as possible, but it will cause the output wind pressure Lower.

(2) Increasing the axial width of the first blade 110, the airflow circulates in the channel of the first blade 110 for a longer distance, so that the airflow can achieve a greater turning in the channel of the first blade 110, the first blade 110 The load received can also increase, which makes V2 more biased to the opposite direction of U1. Since V2 and V3 are in opposite directions, U2 is a fixed value, and V2 is more biased in the opposite direction of U1, which means that W3 is also biased more in the opposite direction of U1. As a result, both the axial outflow W4 and the difference between W4 and W3 (that is, the airflow turning angle of the second blade 210) can be ensured, so that the load of the second-stage impeller 20 is also improved. Therefore, this design can improve the wind pressure and air volume.

In summary, on the basis of the current technology, increasing the axial width of the first blade 110 can not only ensure that the wind direction of the counter-rotating fan 1 remains axial, but also increase the wind pressure and air volume output from the counter-rotating fan 1.

According to the counter-rotating fan 1 of the embodiment of the present invention, since the axial width of the first blade 110 is greater than the axial width of the second blade 210, it can not only ensure that the wind direction of the counter-rotating fan 1 remains axial, but also increase the counter-rotating The air pressure and air volume output by the fan 1.

In some embodiments, the axial width of the first blade 110 is A1, and the axial width of the second blade 210 is A2. A2 does not exceed the relationship of twice A1, that is, A1 and A2 satisfy the relationship: 1 < A1 / A2≤2. It is understandable that excessive A1 / A2 will cause the second blade 210 to extend too short, which will also cause the air flow path of the second blade 210 to be shorter, which will cause the second blade 210 to not withstand too much air flow turning, thus The wind pressure output by the counter-rotating fan 1 is low. As shown in FIG. 7, therefore, controlling the size of A1 / A2 within the range of less than 2 can ensure that the outlet direction of the counter-rotating fan 1 maintains the axial direction, and also ensures the wind pressure and air output from the counter-rotating fan 1.

Preferably, 1.2≤A1 / A2≤1.8. Of course, in other embodiments of the present invention, A1 / A2 can be adjusted according to actual conditions and is not limited to the above range.

In some alternative embodiments, the axial width A1 of the first blade 110 ranges from 25 mm to 55 mm, and the axial width A2 of the second blade 210 ranges from 25 mm to 55 mm. In other words, A1 and A2 satisfy the relationship: 25mm≤A1≤55mm, 25mm≤A2≤55mm. According to the test, the values of A1 and A2 are better manufactured within the above range, which reduces the production cost of the counter-rotating fan 1. Of course, in other embodiments of the present invention, the values of A1 and A2 can be selected according to actual needs, and are not limited to the above ranges.

In some embodiments, as shown in FIGS. 2-3, the edges of each first blade 110 in the circumferential direction are the first leading edge Le1 and the first trailing edge Te1, and the first leading edge Le1 and the first trailing edge are respectively The edges Te1 are all curved in the direction of rotation from the inside to the outside in the radial direction, and the curved protrusion of the first leading edge Le1 faces the first trailing edge Te1 on the corresponding first blade 110. The edges of each second blade 210 in the circumferential direction are the second leading edge Le2 and the second trailing edge Te2, and the second leading edge Le2 and the second trailing edge Te2 rotate toward the radial direction from inside to outside The direction is curved, and the curved protrusion of the second leading edge Le2 faces the second trailing edge Te2 on the corresponding second blade 210.

It can be understood that, since the first leading edge Le1 and the first trailing edge Te1 of the first blade 110 are both curved in the radial direction from the inside to the outside toward the rotation direction, and the second leading edge Le2 of the second blade 210 is The second trailing edge Te2 is curved from the inside to the outside in the radial direction toward the rotation direction, which can effectively weaken the radial component of the surface fluid of the blades of the first blade 110 and the second blade 210, so that the energy is exhausted. It may be concentrated in the axial direction, reducing the radial loss of the first blade 110 and the second blade 210, improving the working efficiency of the counter-rotating fan 1, and increasing the output wind pressure and air volume of the counter-rotating fan 1 to a certain extent.

In addition, the rotation directions of the first-stage impeller 10 and the second blade 210 are opposite, and the bending direction of the first blade 110 is the same as the rotation direction of the first-stage impeller 10, and the bending direction of the second blade 210 is the same as the second-stage impeller 20 The rotation directions are the same, that is, the bending direction of the first blade 110 and the bending direction of the second blade 210 are opposite. This structure can reduce the phenomenon that the first blade 110 and the second-stage impeller 20 periodically overlap during the rotation of the counter-rotating fan 1, so that the depleted flow field from the first blade 110 always enters away from the surface of the second blade 210. In the middle flow channel, the more uniform airflow passes over the surface of the second blade 210. Thus, not only the aerodynamic performance of the second blade 210 is ensured, but also the rotation noise of the second blade 210 is reduced to a certain extent.

In some embodiments, the leading edge bending angle Γ _le of the first blade 110 and the second blade 210 ranges from 15 ° to 75 °. That is to say, the leading edge bending angle Γ _{le of the} first blade 110 and the second blade 210 both satisfy the condition: 15 ° <Γ _le <75 °. The projection of the first leading edge Le1 on the radial section is the first leading edge Le1 line, and the angle between the tangent line and the radial line Ld at any point on the first leading edge Le1 line is the leading edge bending angle of the first blade 110 The projection of the second leading edge Le2 on the radial cross section is the second leading edge Le2 line, and the angle between the tangent line and the radial line Ld at any point on the second leading edge Le2 line is the leading edge bend of the second blade 210 At the angle, the radial section is a plane perpendicular to the rotation axis of the counter-rotating fan 1, and the radial line Ld is a straight line passing through the rotation axis in the radial section.

It can be understood that the first blade 110 and the second blade 210 are curved in the circumferential direction toward their rotation direction, such a blade shape can weaken the radial motion component of the air flow when the first blade 110 and the second blade 210 rotate, Thereby, the motion component of the air flow in the axial direction is increased, that is to say, such an airfoil shape can improve the efficiency of the first blade 110 and the second blade 210. Preferably, Γ _le satisfies the condition: 35 ° <Γ _le <55 °. Of course, what needs additional explanation here is that, in the embodiment of the present invention, the size of Γ _le is not limited to the above range, and the size of Γ _le may be specifically adjusted according to actual conditions. In addition, in the embodiment of the present invention, the leading edge bend angle of the first blade 110 and the leading edge bend angle of the second blade 210 may or may not be the same.

In some embodiments, as shown in FIGS. 2-3, the trailing edge bending angle Γ _te of the first blade 110 and the second blade 210 ranges from 0 ° -60 °. That is, the trailing edge bending angles Γ _{te of the} first blade 110 and the second blade 210 both satisfy the condition: 0 ° <Γ _te <60 °. The projection of the first trailing edge Te1 on the radial section is the first trailing edge Te1 line, and the angle between the tangent line and the radial line Ld at any point on the first trailing edge Te1 line is the trailing edge bending angle of the first blade 110 The projection of the second trailing edge Te2 on the radial cross section is the second trailing edge Te2 line, and the angle between the tangent line and the radial line Ld at any point on the second trailing edge Te2 line is the trailing edge bend of the second blade 210 Angle; the radial section is a plane perpendicular to the rotation axis of the counter-rotating fan 1, and the radial line Ld is a straight line passing through the rotation axis in the radial section.

It can be understood that the first blade 110 and the second blade 210 are curved in the circumferential direction toward their rotation direction, such a blade shape can weaken the radial motion component of the air flow when the first blade 110 and the second blade 210 rotate, Thereby increasing the axial motion component of the airflow. In other words, such a blade shape can improve the efficiency of the first blade 110 and the second blade 210. Preferably, Γ _te satisfies the condition: 20 ° <Γ _te <40 °. Of course, what needs additional explanation here is that, in the embodiment of the present invention, the size of Γ _te is not limited to the above range, and the size of Γ _te may be specifically adjusted according to actual conditions. In addition, in the embodiment of the present invention, the trailing edge bend angle of the first blade 110 and the trailing edge bend angle of the second blade 210 may or may not be the same.

It should be added that when the angle between the leading edge and the trailing edge of the first blade 110 is not equal to the angle between the leading edge and the trailing edge of the second blade 210, the first blade 110 and the first blade 110 can be better avoided. The phenomenon of periodic overlap occurs when the two blades 210 rotate, and the flow field structure can be optimized and the flow field loss can be reduced by optimizing the above-mentioned angle distribution.

In some embodiments, as shown in FIGS. 2-3, the number of the first blade 110 and the second blade 210 are not equal. It can be understood that the number of the first blade 110 and the number of the second blade 210 are not equal, which can avoid the overlap of the wake frequency of the first blade 110 and the blade frequency multiplication of the second blade 210, thereby avoiding the superposition of noise spectrum and the The resonance of the first blade 110 and the second blade 210 is avoided. Of course, in other embodiments of the present invention, the number of the first blade 110 and the second blade 210 may also be the same.

In some embodiments, the first-stage impeller 10 and the second-stage impeller 20 are driven and rotated by two motors, respectively. It can be understood that the first-stage impeller 10 and the second-stage impeller 20 are driven and rotated by two motors, respectively, which can make the first-stage impeller 10 and the second-stage impeller 20 rotate at an arbitrary speed ratio, which greatly avoids the first The resonance phenomenon occurs between the first-stage impeller 10 and the second-stage impeller 20, thereby greatly reducing the working noise of the counter-rotating fan 1. Of course, in other embodiments of the present invention, the first-stage impeller 10 and the second-stage impeller 20 are driven and rotated by the same motor.

In some embodiments, as shown in FIG. 1, the counter-rotating fan 1 further includes a shroud 30 and two mesh covers 40, the shroud 40 surrounds the outer circumferential sides of the first-stage impeller 10 and the second-stage impeller 20, two The net cover 40 is connected to opposite sides of the enclosure 30. Therefore, the safety of the counter-rotating fan 1 during operation can be improved, and the phenomenon that the rotating blade hurts people can be avoided.

In some specific embodiments, the enclosure 30 includes ring ribs and a plurality of transverse ribs. The ring ribs are formed into a ring shape. The plurality of transverse ribs are respectively connected to the ring ribs. Two ends of each transverse rib are respectively connected to the two mesh covers 40. The structure of the enclosure 30 is relatively stable, which further ensures the safety of the counter-rotating fan 1.

In some embodiments, the counter-rotating fan 1 further includes a post, which is connected below the enclosure 30. As a result, the first impeller and the second impeller are at a certain distance from the ground, so as to realize the air outlet at different heights.

The counter-rotating fan 1 according to a specific embodiment of the present invention is described below with reference to FIGS. 1-3.

The counter-rotating fan 1 of this embodiment includes a first-stage impeller 10 and a second-stage impeller 20 with opposite rotation directions, a shroud 30 and two mesh covers 40. The first-stage impeller 10 is located on the air inlet side of the counter-rotating fan 1, The second-stage impeller 20 is located on the outlet side of the counter-rotating fan 1, the first-stage impeller 10 includes a plurality of first blades 110 distributed along its circumferential direction, and the second-stage impeller 20 includes a plurality of second blades distributed along its circumferential direction For the blade 210, the axial width of the first blade 110 is greater than the axial width of the second blade 210. The axial width of the first blade 110 is A1, and the axial width of the second blade 210 is A2. A1 and A2 satisfy the relationship: 1 <A1 / A2≤2. The edges of each first blade 110 on the two sides in the circumferential direction are the first leading edge Le1 and the first trailing edge Te1 respectively, and the edges on the two sides of each second blade 210 in the circumferential direction are the second leading edge Le2 and the second trailing edge, respectively Te2, the leading edge bending angle Γ _{le of the} first blade 110 and the second blade 210 both satisfy the condition: 15 ° <Γ _le <75 °, the trailing edge bending angle Γ _{te of the} first blade 110 and the second blade 210 satisfy the condition : 0 ° <Γ _te <60 °. The first-stage impeller 10 and the second-stage impeller 20 are driven and rotated by two motors, respectively. The mesh cover 40 surrounds the outer peripheral sides of the first-stage impeller 10 and the second-stage impeller 20, and the two mesh covers 40 are connected on opposite sides of the enclosure 30.

In the description of this specification, reference to the descriptions of the terms "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" is meant to be combined with the implementation The specific features, structures, materials, or characteristics described in the examples or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic expression of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art may understand that various changes, modifications, replacements, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, The scope of the invention is defined by the claims and their equivalents.

Claims (10)

1. A counter-rotating fan is characterized by comprising a first-stage impeller and a second-stage impeller rotating in opposite directions, the first-stage impeller is located on the air inlet side of the counter-rotating fan, and the second-stage impeller is located on the On the outlet side of the counter-rotating fan, the first-stage impeller includes a plurality of first blades distributed along its circumferential direction, and the second-stage impeller includes a plurality of second blades distributed along its circumferential direction, the first The axial width of one blade is larger than the axial width of the second blade.
2. The counter-rotating fan according to claim 1, wherein the axial width of the first blade is A1, and the axial width of the second blade is A2, and A1 does not exceed twice A2.
3. The counter-rotating fan according to claim 2, wherein the axial width A1 of the first blade ranges from 25 mm to 55 mm, and the axial width A2 of the second blade ranges from 25 mm to 55 mm.
4. The counter-rotating fan according to any one of claims 1 to 3, wherein each edge of each first blade in the circumferential direction is a first leading edge and a first trailing edge, respectively. Both the leading edge and the first trailing edge are curved toward the direction of rotation in a radial direction from inside to outside, and the bent protrusion of the first leading edge faces the first trailing edge corresponding to the first blade ; The edges of each of the second blades on the two sides in the circumferential direction are the second leading edge and the second trailing edge, respectively, the second leading edge and the second trailing edge are in a radial direction from inside to outside Curved toward the direction of rotation, the curved protrusion of the second leading edge faces the second trailing edge on the corresponding second blade.
5. The counter-rotating fan according to claim 4, wherein the leading edge bending angle Γ _l of the first blade and the second blade is in the range of 15 ° -75 °; wherein,

   The projection of the first leading edge on the radial section is the first leading edge line, and the angle between the tangent line and the radial line at any point on the first leading edge line is the leading edge curve of the first blade angle;

   The projection of the second leading edge on the radial section is the second leading edge line, and the angle between the tangent line and the radial line at any point on the second leading edge line is the leading edge bend of the second blade angle;

   The radial section is a plane perpendicular to the rotation axis of the counter-rotating fan, and the radial line is a straight line passing through the rotation axis in the radial section.
6. The counter-rotating fan according to claim 4, wherein the trailing edge bending angle Γ _te of the first blade and the second blade ranges from 0 ° to 60 °; wherein,

   The projection of the first trailing edge on the radial section is the first trailing edge line, and the angle between the tangent line and the radial line at any point on the first trailing edge line is the trailing edge bend of the first blade angle;

   The projection of the second trailing edge on the radial section is the second trailing edge line, and the angle between the tangent line and the radial line at any point on the second trailing edge line is the trailing edge bend of the second blade angle;

   The radial section is a plane perpendicular to the rotation axis of the counter-rotating fan, and the radial line is a straight line passing through the rotation axis in the radial section.
7. The counter-rotating fan according to any one of claims 1 to 6, wherein the number of the first blades and the number of the second blades are not equal.
8. The counter-rotating fan according to any one of claims 1-7, further comprising: an enclosure and two net enclosures, the net enclosure surrounding the first-stage impeller and the second stage On the outer peripheral side of the impeller, the two net covers are connected on opposite sides of the enclosure.
9. The counter-rotating fan according to claim 8, wherein the enclosure includes a ring rib and a plurality of horizontal ribs, the ring ribs are formed into a ring shape, and the plurality of the horizontal ribs are respectively connected to the ring ribs, each Two ends of each of the transverse ribs are respectively connected to the two net covers.
10. The counter-rotating fan according to claim 8, further comprising: a vertical column, the vertical column being connected below the enclosure.

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