JP3048438B2 - Mixed flow fan - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for automobiles and outdoor units for air conditioning, etc., and has a shape and a structure that efficiently cools a heat exchanger. Regarding fans.

[0002]

2. Description of the Related Art Conventionally, axial fans have a wide range of uses because of their small size and high air volume, and the following two modes are available. The first aspect, like a fan or blower,
A so-called pressureless open type in which there is no pressure resistor on the suction side or the discharge side near the fan. The second mode is radiator fan for automobile, fan for oil cooler,
There is a pressurized type, such as a cooling / heating fan or the like, where there is some pressure resistor on the suction side or the discharge side, or when it is used in a pressurized state with ram wind.

[0003] However, the design philosophy of each of them is almost the same, and the same use is fundamentally performed in a place where the air flow is different, as in the case of using a pressureless open type fan as a pressure type fan. Therefore, they are often inefficient and use inefficiently with high noise. If the pressure type fan is described in detail, in recent years, with the increase in the output of engines, plants, air conditioners, etc., it has been required to improve the cooling efficiency of the heat exchanger, and various types of high air flow, low driving force loss, low noise, etc. There is a demand for a blower fan that meets the conditions.
Further, in order to increase the amount of air passing through the heat exchanger, the heat exchanger and the blower fan are connected using a shroud.
There is an optimum value for the positional relationship between the blower fan and the shroud.
6, the axial fan F of the shroud 9 as shown in FIG.
_By increasing the fog to ₀ (3/4 or more), high air volume and high efficiency can be obtained. However, recently heat exchangers
Further improvement of the cooling capacity of the heat exchanger by increasing the output is required, and the density of the fin core is increased and the thickness of the core is increased. In addition, due to the high performance of the car, the interior of the engine room is equipped with various control devices and electrical components, so that there is no empty space and the pressure resistor such as the engine is close to the blower fan. As a result, the pressure loss increases.

As described above, when the inside of the engine room becomes a high pressure loss field, the air flow on the fan blade surface of the blower fan flows obliquely in the centrifugal direction, and the discharge flow of the blower fan is also directed in the centrifugal direction. For this reason, the efficiency of the conventional axial fan is deteriorated, and the cooling capacity is reduced. As a countermeasure, the blade mounting angle is increased to 40 ° to 45 ° so as to generate a centrifugal flow, and the cover ratio of the shroud to the fan is reduced. However, when the mounting angle of the wing is increased, the separation of the air flow from the fan blade is quick, the turbulence area is increased, and the wake width affecting the turbulent noise is wide, which causes the noise to increase. . Also, when the angle of attachment of the wings is increased, the power consumption and the vehicle speed wind increase, and the fan becomes resistant to the vehicle speed wind, which leads to a large increase in power. That is, the tangential component of the lift increases, and the driving force increases as the reaction force.

[0005] In order to improve these, a blade shape has been conceived which suppresses the diagonal flow and makes the flow as axial as possible (JP-A-64-397). But,
When an automobile is installed, an engine or the like exists as ventilation resistance behind the blowout, so this becomes a large ventilation resistance,
Not efficient. Therefore, in order to obtain a high air flow, it is necessary to positively form a diagonal flow so that the air flow avoids obstacles. Most of the conventional mixed flow fan has a plurality of blades planted in a boss portion having a truncated cone shape, and is almost the same in terms of air volume as an axial fan. Also, in the conventional mixed flow fan, the ratio of the conical surface in the front projected area is large, the flow path is narrowed, the fan itself has a large ventilation resistance, and the cooling capacity is greatly reduced.
Has problems that need to be solved practically
No. 98).

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional fan, and as a fan suitable for a high pressure loss field, has a high air volume, a low driving force, a high fan system efficiency, and a low noise. The aim is to provide a mixed flow fan to achieve. Still another object of the present invention is to provide a mixed flow fan in which the fogging rate between the fan and the shroud is set to a certain optimum value in consideration of the flow field and the high performance is exhibited in a wide operating range. I do.

[0007]

SUMMARY OF THE INVENTION A mixed flow fan F according to the present invention is provided.
As shown in FIGS. 1 and 2, a plurality of fan blades protruding around a boss portion that is driven to rotate have a substantially polygonal shape from a front edge to a rear edge thereof. The leading edge of the joint between the blade and the boss on the side, the leading edge,
A substantially triangular first region I defined by an outer edge rear end portion, which is a terminal position closer to the trailing edge side from the center of the outermost edge portion, has an axial flow blade shape, and is joined to the boss portion on a discharge side with the boss portion. From the boss to the boss, and from the rear edge of the boss to the rear edge of the outer diameter of the blade, and from the rear edge of the outer diameter of the blade to the front edge of the blade. A substantially polygonal second region II defined by a blade trailing edge portion including a centrifugal trailing edge portion reaching the discharge end portion toward the edge side is formed into a centrifugal flow blade shape, and the first region I on the suction side and the discharge side are formed. A substantially triangular third region III connecting the second region II with a continuous curved surface has a mixed flow blade shape, and the center line of the third region III, that is, the third region of the first region on the suction side is formed. The tangent curve and the curve tangent to the third area of the second area on the discharge side are defined at each radial position. A curved line connecting the center positions of the straight lines connected together is formed by a curved surface that recedes backward and inclines with respect to the rotation direction, and the center line of the third region III moves rearward from the suction side toward the discharge side. The axial flow of the first region I and the centrifugal flow of the second region II are mixed by the third region, and are mixed in the diagonal flow direction between the axial direction and the radial direction. It is formed in a shape to blow air. Here, the outermost edge refers to the mixed flow fan of the present invention as shown in FIG.
When viewed from the front, the outermost edge of the blade is substantially arc-shaped, is a substantially arc-shaped portion having a curvature r about the fan rotation axis, and extends from the front edge of the outer edge to the rear edge of the outer edge. That is, in the mixed flow fan of the present invention, the outermost edge portion is closer to the rear edge side than the outermost edge center on the outermost edge portion from the outer edge front end portion.
This is a substantially arc-shaped portion that reaches the rear end of the outer edge that is the terminal position. Also, the diagonal flow outer edge refers to a space between the rear end of the outer edge (existing on the outermost edge) and the discharge end. The centrifugal trailing edge refers to a space between the discharge end and the outer diameter trailing edge (located closer to the axial center than the outermost edge on the trailing edge). The outer edge of the diagonal flow and the trailing edge of the centrifugal flow are on a substantially circular arc having the same curvature from the outer edge rear end on the outermost edge to the outer diameter rear edge on the rear edge, and are different from the outermost edge. It is formed in a substantially arc shape having a curvature. For this reason, the boundary between the outermost edge and the mixed flow outer edge is the rear edge of the outer edge, and the boundary between the centrifugal rear edge and the rear edge is the outer diameter rear edge.
The distal trailing edge is included in the trailing edge. Also, the blade trailing edge from the joining trailing edge to the blade outer diameter trailing edge and heading toward the leading edge is the blade trailing edge from the joining trailing edge with the boss to the blade outer diameter trailing edge. A blade trailing edge including a centrifugal trailing edge extending from the outer diameter trailing edge toward the leading edge to the discharge end. Further, the center line of the third region is a center position of each straight line connecting at each radial position a curve contacting the third region of the first region on the suction side and a curve contacting the third region of the second region on the discharge side. Is a curve that connects. Also, the curved surface retreating with respect to the rotation direction is, when the mixed flow fan is viewed from the front, retreats backward and inclines with respect to the rotation direction, that is, from the inner peripheral side to the outer peripheral direction in the reverse direction toward the rotational direction. A curved surface that draws a substantially parabola or a substantially circular arc extending in the direction shown in FIG. Further, the curved surface that retreats from the suction side toward the discharge side is, when the mixed flow fan is viewed from the side, a substantially parabolic or substantially circular arc extending from the inner side to the outer side toward the discharge side from the suction side. The surface to be drawn.

[0008]

According to the mixed flow fan of the present invention having the above-described structure, since the substantially polygonal fan blade is formed by the plurality of curved surfaces, the flow is rapidly refracted which causes vibration, noise, and the like. Can be avoided and air can be quietly and efficiently blown in the diagonal flow direction. In other words, the suction airflow from the axial direction of the fan is provided with the axial flow component efficiently and accurately in the first region I of the axial flow blade region of the fan blade, and flows backward. Then, a centrifugal flow component is applied and flows in the second region II of the centrifugal flow blade region. These two flows are mixed stably and smoothly in the third region III of the mixed flow blade region where the mixed flow component is applied before reaching the discharge side of the fan blade. Thereafter, the airflow is efficiently discharged obliquely rearward from the discharge side of the fan blade. For this reason, the mixed flow fan of the present invention achieves many practical effects such as high air volume, low driving force, low noise, and high efficiency.

[0009]

[Other inventions] The mixed flow fan of the second invention has an outer diameter shape as shown by a broken line in FIGS. 1 and 2, in which the above-mentioned fan blade is joined from the rear edge of the boss on the discharge side. A joining portion with the boss portion reaching the joining front edge end with the boss portion,
From post-splicing edge portions of said boss portion, blade reaches the blade outer径後edge portion positioned on the axial center toward from the outermost edge
From the rear edge of the outer diameter toward the leading edge
Bending from the outermost edge to the discharge end located on the inner diameter side on the radial side
A substantially polygonal second region II defined by a blade trailing edge including a centrifugal trailing edge formed by a line is formed into a centrifugal flow blade shape, and the first region I on the suction side and the second region I on the discharge side are formed. A substantially triangular third region III connecting the region II with a continuous curved surface has a mixed flow blade shape. Where the figure
1, the broken line in FIG. 2 indicates the mixed flow fan of the second invention.
Indicates the outer edge of the diagonal flow and the trailing edge of the centrifuge.
The trailing edges of the nodes are not connected by a substantially circular
Circle without forming an arc from the outer diameter trailing edge located at the center
Inside diameter side from arc, outside diameter side from outside diameter trailing edge, outermost edge
It is formed by a curve reaching the discharge end located on the inner diameter side
After the centrifugal trailing edge and the outer edge without forming an arc from the discharge end
The diagonal flow outer edge formed by the curve reaching the end is shown.
The mixed flow fan of the second invention having the above configuration can further promote the flow of the mixed flow in the mixed flow direction between the axial direction and the radial direction, and has practical effects such as elimination of components. .

A mixed flow fan according to a third aspect of the present invention has the fan blade described above, openings at both ends, a large diameter portion and a small diameter portion at opposite ends in the axial direction, and a smooth curve therebetween. A shroud formed by the formed hollow cylindrical body, comprising a shroud configured, and inserting the first region of the axial flow blade shape in the fan blade toward the large diameter portion from the minimum inside diameter portion in the small diameter portion of the shroud, A centrifugal flow blade-shaped second region of the fan blade is disposed in an open relationship with the shroud.

In the mixed flow fan according to the third aspect of the present invention, since a substantially polygonal fan blade is formed by the plurality of curved surfaces, and the fan blade is disposed in an appropriate positional relationship with respect to the shroud, Abrupt refraction of the flow, which causes vibration, noise, and the like, can be avoided, and air can be quietly and efficiently blown in the diagonal flow direction. That is,
The suction airflow from the axial direction of the fan flows rearward in the first region of the axial blade shape of the fan blade in which the axial flow component is efficiently and accurately applied. Then, a centrifugal flow component is applied and flows in the second region of the centrifugal flow blade shape. These two flows are mixed stably and smoothly in the third region of the mixed flow blade shape that provides a mixed flow component before reaching the discharge side of the fan blade. Thereafter, the airflow is efficiently discharged obliquely rearward from the discharge side of the fan blade. Therefore, the mixed flow fan of the present invention achieves many practical effects such as high air volume, low driving force, low noise, and high efficiency.

In the mixed flow fan according to the third aspect of the present invention, the fan blades are disposed in an appropriate positional relationship with respect to the shroud, so that the circulating flow that interrupts the suction air flow from the side and the flow from the side. Flow can be prevented and a smooth suction air flow can be formed. Also, by forming the shroud with a smooth curve, as a result, the flow across the blade and the discharge air flow can also be smoothed. Further, due to the diagonal flow formed by the fan blades constituted by the plurality of curved surfaces, it is possible to suppress the occurrence of the backflow between the shroud and the fan blade, which is a problem in the conventional ordinary fan. Thus, the mixed flow fan according to the third aspect of the present invention provides a smooth suction air flow by preventing the circulating flow, the flow from the side and the backflow.
A flow across the blade and a discharge air flow can be formed. As a result, practically excellent operational effects such as improving the air volume and the fan efficiency and reducing the noise generated due to the circulating flow, the lateral flow, and the backflow are exhibited.

Further, the mixed flow fan according to the third aspect of the present invention, when applied to a suction type in which a large diameter portion of the shroud, that is, a configuration in which a resistor such as a heat exchanger and a filter exists upstream of the flow, is used. A room surrounded by the resistor, the shroud, and the fan is formed, and the shroud can prevent a circulating flow from the discharge side to the suction side of the fan and a flow generated from the circulating flow from the upstream side of the fan. . Further, the mixed flow fan according to the third aspect of the present invention, by preventing a strong backflow from the discharge side to the suction side through the gap between the fan tip and the shroud having a speed component in the opposite direction due to the mixed flow, creates a negative pressure in the room. State, a large pressure gradient is formed with respect to the atmospheric pressure on the upstream side of the low pressure antibody such as the heat exchanger and the filter, and a large amount of suction medium is sucked in through the low antibody. Can be effectively achieved. As a result, a large pressure difference is created from the fan to the downstream of the flow, so that a large amount of discharge flow can be formed, and the efficiency is improved. In this case, it is particularly effective when a large low antibody is present on the discharge side of a fan such as an engine in an automobile cooling fan. In other words, the conventional ordinary axial flow fan has a drawback that when an engine having a large low antibody is present on the discharge side, the main axial flow is blocked by the low antibody, and the blowing efficiency is greatly reduced. However, in the mixed flow fan according to the second aspect of the present invention, since a strong mixed flow of air is formed by the fan blades, a flow along the wall of the engine can be formed, the flow does not collide with the resistor, and the blowing efficiency is improved. Without a decrease in pressure, a large pressure gradient before and after the fan works in synergy with the above effect to allow a large amount of air to be sucked in through a radiator (heat exchanger) and discharge a large amount of air into the engine room. Therefore, the heat exchange function of the radiator is effectively achieved, and a strong flow is formed in the engine room, so that the generation of heat pool due to the exhaust device and the like is prevented, the temperature in the engine room is reduced, and the fuel supply device is reduced. And other problems such as malfunction of the device and failure of the exhaust device.

Further, the mixed flow fan according to the third aspect of the present invention is configured such that in the push type, low antibodies such as a heat exchanger, a filter, and various devices that generate heat are present on the large diameter portion of the shroud, that is, on the downstream side of the flow. When applied, a room surrounded by the fan, shroud and low antibody is formed, and the circulating flow and backflow from the discharge side to the suction side are reliably shut off by the shroud and the mixed flow of air from the mixed flow fan of the third invention. Then, the inside of the room can be set to a high pressure. In addition, since the air blowing region can be expanded obliquely rearward to form a diagonal air flow, the discharge flow can be uniformly passed over the entire surface of the low antibody such as the heat exchanger and the filter. Exchange function can be effectively achieved. In addition, if the shroud is formed and disposed along the air diagonal flow formed by the diagonal flow fan of the third invention, the shroud can be provided in a larger area than the conventional normal axial flow fan in which the discharge flow is restricted on the discharge side. Since the air can be blown over, there is an advantage that a small fan can blow air to a low antibody such as a large heat exchanger.

[0015]

An embodiment of the present invention will be described in detail with reference to the drawings. The mixed flow fan according to the present embodiment is applied to a cooling fan driven by an engine for a radiator as a cooling system of an automobile. Prior to the description, a current automobile cooling system will be briefly described. FIG. 3 shows the layout of a commonly used automotive cooling system. The structure of the cooling system 2 of the engine room 1 of the automobile is as follows: an engine block 4 and other accessories on the discharge side 3 of the fan F ₁ , and a radiator 6, an air conditioner condenser 7 and a grill 8 on the suction side 5. and consists of the shroud 9 for annexed to the radiator 6 suffer from fan F _1. The provision of the shroud 9 lowers the pressure on the suction side 5 of the fan. As a result, since the pressure difference between the radiator 6 and the air passage inlet / outlet of the air conditioner condenser 7 is increased, it is necessary to improve the cooling and the blowing efficiency in order to improve the flow of the air 10. In the suction side 5, since the enclosing radiator 6, a large consisting cooling of the pressure resistance such as an air conditioning capacitor 7 in the shroud 9, the discharge side 3 by the rotation of the fan F _1, a large pressure difference between the suction side 5 Occurs. Then, the air 10 passing through the radiator 6, since the low antibody on the discharge side 3 of the fan F ₁ becomes an obstacle of the vent such as an engine block 4 is present, lower the rear of the fan F ₁ is the pressure resistance becomes high The air flow 11 is bent outward and discharged. Further, due to the pressure difference, the fan F
_{Since the} backflow 12 is generated through the gap between the shroud ₁ and ₁ , only a part of the discharge air from the fan F ₁ passes through the radiator 6, and the cooling and blowing efficiency is greatly reduced. In order to prevent the backflow 12, there is a method of reducing the clearance δ. However, in general, the clearance δ cannot be reduced so much because of the relative vibration between the fan and the shroud. Further, when the clearance is large, the utilization rate of the ram wind R at a high speed of the vehicle can be increased by reducing the ventilation resistance of the ram wind R. Further, from the above, for example, the larger the clearance is, the higher the productivity is, and so on.

Therefore, in order to increase the efficiency of cooling and blowing, it is considered to be better to prevent the backflow by making the air flow by the fan better than making the clearance smaller, without the ram wind and productivity problems. Thus, when considering a fan with a shroud, it is a good idea to form a fan that matches the flow in order to increase the efficiency. Therefore, in the cooling system 2 having a large pressure difference, the air flow is such that the fan discharge air 11 flows outward. Since the flow on the fan blade surface is also affected by the pressure difference, it is important that the flow on the blade surface be a three-dimensional oblique flow in which a centrifugal flow is added to an axial flow.

The mixed flow fan of this embodiment satisfies the above requirements, and will be described in detail below with reference to FIGS. As shown in FIGS. 4 to 7, the mixed flow fan F1 of this embodiment is provided with a plurality of protruding portions around the boss 13 which is driven to rotate, and the shape of the blade from the front edge 16 to the rear edge 19 is substantially polygonal. It is a fan blade 14 formed in a shape. The fan blade 14 has a front edge 30 at the suction side 5 where the blade 14 and the boss 13 are joined, and a front edge 1 at the suction side 5.
6 and the substantially triangular first region 18 defined by the outer edge rear end portion 31 which is a terminal position closer to the rear edge side than the center of the outermost edge portion 17, the axial flow component is added to the suction air flow from the fan axial direction. An axial blade shape to be applied and blown. Further, the fan blade 14 is connected to the boss 13 on the discharge side 3.
A joining portion 15 between the blade 14 and the boss portion 13 extending from a joining rear edge portion 32 to the joining front edge portion 30 to the boss portion 13, and a joining rear edge portion 32 to the boss portion 13 From the outermost edge 17 to the blade outer diameter trailing edge 33 which is located closer to the axial center than the outermost edge 17, and from the outer diameter trailing edge 33 to the front edge side, the outer diameter side of the outer diameter rear end 33, the outermost edge 17. A substantially polygonal second region 20 defined by a blade trailing edge 19 including a centrifugal trailing end formed by a curve reaching the discharge end 34 located on the inner diameter side is formed in a centrifugal flow blade shape. The substantially triangular third region 21 connecting the first region 18 on the suction side and the second region 20 on the discharge side with a continuous curved surface has a mixed flow blade shape, and the center line of the third region III That is, a curve connecting the center position of each straight line connecting the curve contacting the third region 21 of the suction-side first region 18 and the curve contacting the third region 21 of the discharge-side second region 20 at each radial position. Is formed with a curved surface that recedes backward and inclines with respect to the rotation direction, and the center line of the third region 21 is formed with a curved surface that recedes backward and inclines from the suction side toward the discharge side, The axial flow in the first region 18 and the centrifugal flow in the second region 20 are mixed by the third region 21 and are formed so as to blow in a diagonal flow direction between the axial direction and the radial direction. A substantially triangular region 23 defined by the discharge side joining end portion 15 with the boss portion 13 and the rear edge portion 19 of the discharge side 3 has:
A plate is formed for reinforcement and rectification so that the blade and the plate do not overlap when viewed from the front of the fan. The shroud 9 has openings at both ends, has a large-diameter portion and a small-diameter portion at opposite ends in the axial direction, and is constituted by a hollow cylindrical body having a smooth curve therebetween. Then, the mixed flow fan F1 of this embodiment is used.
Inserts the first area 18 of the axial flow blade area of the fan blade 14 toward the large diameter part from the minimum inner diameter part of the small diameter part of the shroud 9 and the second area of the centrifugal flow blade area of the fan blade 14. 20
Are arranged in an open relationship from the shroud 9.

[0018] Thus, the present embodiment is a centrifugal flow is shallow disposed so as efficiently generate fog for fan F ₁ of the shroud 9. The fan F _1, when viewed from the front, axial outer diameter side, the boss portion is in the configuration of the centrifugal fan. However, both are connected by a smooth curve, and are formed so as to generate a smooth flow.
The one-dot chain line is a line dividing the axial flow portion and the centrifugal flow portion. Looking at the cross section in the circumferential direction at each radius, the axial flow portion: centrifugal flow portion = 1: 3 in the boss portion, and the axial flow portion in the outer diameter portion: Centrifugal flow part = 3: 1
The ratio is changing. The blade installation angle on the axial flow side is 2
The angle is set to about 0 to 30 ° so that when the vehicle speed is large, the wind power is used to reduce the required power.

When viewed from the side, the inlet side has an axial flow,
The outlet side is configured to be a centrifugal flow, the two are connected by a smooth curve, and the dashed line is a line dividing the axial flow portion and the centrifugal flow portion. The outlet of the air flow is formed so as to face diagonally backward, and the combination with the shroud 9 reduces the fog to 1/4 to 3 /.
4 so that the distal side is outside the shroud.

The mixed flow fan F according to the present embodiment having the above-described structure is used.
₁ is that a substantially polygonal fan blade 14 is constituted by the plurality of curved surfaces, and the fan blade 14 is disposed in an appropriate positional relationship with respect to the shroud 9. Abrupt refraction can be avoided, and air can be quietly and efficiently blown in the diagonal direction. In other words, the suction airflow from the fan axial direction flows rearward while the axial flow component is efficiently and accurately applied to the fan blade 14 in the first region 18 of the axial flow blade region, and flows in the centrifugal flow blade region. In the two regions 20, the centrifugal flow component is applied to flow, and both flows flow to the discharge region 3 of the fan blade 14 until the third region 21 of the mixed flow blade region that applies the mixed flow component.
Thus, the airflow is efficiently and obliquely discharged from the discharge side of the fan blades obliquely rearward. For this reason, the mixed flow fan of this embodiment is F ₁
Achieves many practical effects such as high air flow, low driving force, low noise, and high efficiency.

In the mixed flow fan F ₁ of the present embodiment having the above-described configuration, the fan blade 14 having the plurality of curved surfaces is provided by disposing the fan blade 14 in an appropriate positional relationship with respect to the shroud 9. The generation of the backflow between the shroud 9 and the fan blade 14, which is a problem in the conventional normal fan, can be suppressed by the mixed flow formed by the above. In addition, in the present embodiment, a circulating flow and a flow from the side that interrupt the suction air flow from the side can be prevented, so that a smooth suction air flow is formed. Further, by forming the shroud 9 with a smooth curve, as a result, the flow across the fan blade 14 and the discharge air flow can also be smoothed. As described above, the mixed flow fan F ₁ of the present embodiment prevents the circulating flow, the flow from the side and the backflow, thereby forming the flow across the smooth suction air flow blade and the discharge air flow, In addition to improving the air volume and the fan efficiency, the present invention has practically excellent operational effects such as reducing the noise caused by the circulating flow, the lateral flow, and the backflow.

The specification performance comparison between the mixed flow fan of this embodiment and the conventional fan shown in FIG. 17 will be described below.

[Table 1]

FIG. 12 is a diagram comparing the mixed flow fan of the present embodiment with the conventional fan, with the flow coefficient φ on the horizontal axis and the power coefficient λ on the vertical axis. The power of the mixed flow fan of the present embodiment is reduced over the conventional fan over the entire use area. The operating point power coefficient decreased by -23.5%. This is because, as a result of reducing the blade installation angle by making the inflow side of the blade an axial flow configuration, the resistance to the vehicle speed was reduced and the air flow became smooth. FIG. 13 shows the flow coefficient φ on the horizontal axis and the efficiency η on the vertical axis.
Are the results of comparison. Compared to the conventional fan, the mixed flow fan of the present embodiment has an increase of + 13.9% at the highest efficiency. It is quite difficult to increase the maximum efficiency with a conventional fan, and the maximum efficiency could be increased by 10% or more by employing the mixed flow fan of this embodiment. FIG. 14 shows the results of comparison with the horizontal axis representing the fan speed _NF and the vertical axis representing the noise value _NL . The suction side and outer diameter side are designed to be axial flow, and the wing mounting angle is reduced, resulting in a smaller wake width from the trailing edge of the wing, which causes turbulent noise. Approximately 4 dB lower noise for the fan. FIG.
5 shows the results of flow coefficient phi, the vertical axis were compared taking specific noise K _S on the horizontal axis. As can be seen from the above results, as a result of significantly reducing power consumption and noise, the specific noise was reduced by about -7 dB over the conventional fan at all flow rates. Note that the mixed flow fan of the present invention has four fan blades for the boss.
10 to 10 can be provided, and the outer diameter of the electric fan can be 250φ to 300φ, and the other diameter can be 300φ to 600φ or more. Further, the mixed flow fan of the present invention is not limited to the above-described embodiment, and can be applied to a fan for an outdoor unit of a heat pump and a fan for an indoor unit of an air conditioner.

[Brief description of the drawings]

FIG. 1 is a fragmentary front view showing a typical mixed flow fan according to the present invention;

FIG. 2 is a cutaway side view of a main part showing a typical mixed flow fan of the present invention.

FIG. 3 is a schematic diagram schematically showing a cooling system to which the mixed flow fan according to the first embodiment of the present invention is applied;

FIG. 4 is a fragmentary front view showing a mixed flow fan according to an embodiment;

FIG. 5 is a cutaway side view of a main part showing the mixed flow fan of the embodiment.

FIG. 6 is a perspective view of the mixed flow fan according to the embodiment, in which main parts are cut away.

FIG. 7 is a side view showing the relationship between the mixed flow fan and the shroud of the embodiment.

8 is a sectional view taken along the line VIII-VIII in FIG. 7;

9 is a sectional view taken along line IX-IX in FIG. 7;

FIG. 10 is a sectional view taken along line XX in FIG. 7;

11 is a sectional view taken along the line XI-XI in FIG.

FIG. 12 is a diagram showing power characteristics of the mixed flow fan according to the embodiment.

FIG. 13 is a diagram showing efficiency characteristics of the mixed flow fan of the embodiment.

FIG. 14 is a diagram showing noise characteristics of the mixed flow fan according to the embodiment.

FIG. 15 is a diagram showing specific noise characteristics of the mixed flow fan of the embodiment.

FIG. 16 is a diagram showing pressure loss caused by a conventional axial fan.

FIG. 17 is a side view showing a relationship between a conventional axial fan and a shroud.

[Explanation of symbols]

F, F ₁ Mixed flow fan R Ram style 3 Discharge side 5 Suction side 9 Shroud 13 Boss 14 Fan blade 16 Front edge 17 Outside diameter end I, 18 First area II, 20 Second area III, 21 Third area

Claims (1)

(57) [Claims] 1. A rotatably driven fan blades in which a plurality of projecting Ri circumferential boss is, the shape of the blade leading from the leading edge to the trailing edge and substantially polygonal shape, before bonding between the blade and the boss portion of the suction side edge Ends and
A substantially triangular first region defined by a front edge portion and an outer edge rear end portion which is a terminal position closer to the rear edge side than the center of the outermost edge portion has an axial flow blade shape, and the boss portion on the discharge side is formed. A joining portion with the boss portion from the joining rear edge portion to the joining front edge portion with the boss portion, and a blade outer diameter from the joining rear edge portion with the boss portion to the blade outer diameter rear edge portion, A substantially polygonal second region defined by a blade trailing edge including a centrifugal trailing edge from the trailing edge toward the leading edge to the discharge end has a centrifugal flow blade shape, and the first region on the suction side. A substantially triangular third region that connects the second region on the discharge side with a continuous curved surface has a diagonal flow blade shape, and the center line of the third region is inclined backward and backward with respect to the rotation direction. It is formed in a curved surface, and the center line of the third region is located rearward from the suction side to the discharge side. The axial flow of the first region and the centrifugal flow of the second region are mixed by the third region, and the air is blown in the diagonal flow direction between the axial direction and the radial direction. A mixed flow fan characterized in that the fan is formed in a shape that allows the fan to flow.