JPH01193099A - Impeller of centrifugal flower - Google Patents

Abstract

PURPOSE:To reduce noises and improves efficiency by specifying relations between vane length and vane thickness/acting face, and decreasing width of a flow passage as it goes from an inlet to an outlet end side. CONSTITUTION:Vanes 7 of an impeller 3 are wing-shaped. In the vanes 7 of the impeller 3, a measurement ratio (Wm/c) of a maximum thicknesses Wm9 of vanes against vane lengths (c) between an inlet end and outlet end of an inflow passage is ranged between 0.14 and 0.16. A measurement ratio (Lm/C) of the vane lengths C between the inlet end and outlet end against a maximum distance Lm between a line from the inlet to the outlet end acting faces ranges from 0.2 to 0.3. Widths of flow passages 13 between the vanes next to each other decrease as they go from the inlet to the outlet end sides. Noise generation can be prevented surely, while efficiency can be improved enough.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an impeller for a centrifugal blower used in an air conditioner or the like.

(Prior art) The impeller of a centrifugal blower has a plurality of long blades attached to the outer periphery of the impeller that extend in the axial direction, and as the impeller rotates, air taken in from the inside is blown out to the outside. It is.

The impeller of this type of centrifugal blower was provided with thick blades as in the past, but in order to reduce noise and improve efficiency, for example, Japanese Patent Application Laid-Open No. 156997/1983 discloses A structure has been proposed in which the wall thickness is gradually reduced from the inside to the outside. According to the impeller disclosed in this publication, it is possible to reduce separation of the airflow flowing along the blades and to reduce the occurrence of turbulence near the blades.

(Problem to be Solved by the Invention) However, the noise and reduction in efficiency in centrifugal blowers are not only caused by the flow condition of air flowing along the blades, but also by the fact that the impeller is retracted after the air is blown out from the impeller. This is also thought to be caused by the conditions in which the air blows against the case of the centrifugal blower. Therefore, there is a problem in that the impeller of the conventional centrifugal blower cannot sufficiently prevent noise and improve efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide an impeller for a centrifugal blower that can reliably prevent noise and sufficiently improve efficiency.

(Means for Solving the Problems) In order to solve the above problems, the impeller of the centrifugal blower of the present invention has a plurality of blades extending in the axial direction on the same circumferential surface, and the blades adjacent to each other are In an impeller of a centrifugal blower that forms a flow path between a pressure surface 11 and a negative pressure surface 12 and blows air from the inside to the outside by centrifugal force, the blades of the impeller are as shown in FIG. It has an airfoil shape, and the dimension ratio (Wm/C) of the maximum thickness W of the blade to the length C of the blade between the inlet end and the outlet end is 0.14 or more and 0.1
6 or less, the size ratio (Lm/C) of the maximum value L1 in the distance between the line S connecting the inlet end and the outlet end and the pressure surface to the length C of the impeller between the inlet end and the outlet end is 0. The width of the flow path between the blades adjacent to the impeller is set to be 0.3 or more, and the width dimension of the flow path between the blades adjacent to the pressure plate gradually decreases from the inside to the outside of the impeller.

Further, when the angle formed by the tangent M of the pressure surface forming the flow path at the base end of the blade and the tangent N of the impeller is defined as the exit angle A, the exit angle A should be 5 degrees or more and 20 degrees or less. is preferred.

Furthermore, the center line G connecting the center of the impeller at the tip of the blade
When the angle between the normal H and the tangent J to the pressure surface at the tip is the artificial angle B, the entrance angle B is 70 degrees or more and 95 degrees
It is preferable that the temperature is less than 1.

Also, the line S connecting the base end and tip of the blade and the center m of the impeller
When the angle formed with G is defined as the mounting angle, the mounting angle is preferably 30 degrees or more and 50 degrees or less.

(Function) When using the impeller of the centrifugal blower configured as described above, the ratio of the blade thickness W to the blade length C (Wm
When /C) is smaller than 0.14, the speed of air flow on the negative pressure surface becomes low and the air separates, and when it is larger than 0.16, the sucked air collides at the blade inlet, resulting in a large loss resistance.

Also, the ratio of the distance L1 of the pressure surface to the length C of the blade (L
If m/C) is smaller than 0.2, the exit angle will be large and the impact when the blown wind collides with the case will be large, and if it is larger than 0.3, air separation will occur on the negative pressure surface.

Furthermore, by gradually reducing the width of the air flow path, the flow velocity of the blown air can be increased, so the blowing efficiency can be improved, and the flow velocity on the negative pressure side is faster than the flow velocity on the pressure side. can prevent air separation.

Note that if the air outlet angle A is larger than 20 degrees, the resistance when the blown air hits the case becomes large and the desired effect cannot be obtained, and if it is smaller than 5 degrees, the air may separate on the negative pressure surface. This occurs, making it impossible to obtain a predetermined amount of airflow and causing noise.

Furthermore, by limiting the air inlet angle B to 70 degrees or more and 95 degrees or less, air can be taken in smoothly along the blades, which prevents turbulence in the air flowing along the blades and reduces noise. Efficiency can be improved.

In this case, if the angle is less than 70 degrees, the air flowing radially will collide with the inlet of the suction surface of the blade, increasing the resistance during intake, and if it is more than 95 degrees, the air flowing along the suction surface of the blade will separate. Disturbances such as vortices occur.

In addition, the mounting angle is preferably 30 degrees or more and 50 degrees or less,
If the angle is smaller than 30 degrees, the air flowing radially collides at the inlet of the suction surface of the blade, increasing resistance during suction, and if it is larger than 50 degrees, separation tends to occur on the suction surface.

(Examples) Examples of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 5, the centrifugal blower 1 has a substantially cylindrical impeller 3 housed inside a case 2.
The air taken in from the center by the rotation of Case 2
The air is guided inside in a spiral manner and is blown out from the air outlet 4.

As shown in FIGS. 3 and 4, the impeller 3 has 42 blades extending radially inward on its outer peripheral surface. The impeller 3 has an air intake 5 formed on one side in the axial direction thereof, and the other side is blocked by a wall 6, and a shaft for rotationally driving the impeller is connected to the impeller 3. It has become.

The impeller 3 is integrally molded from a metal material or a synthetic resin material using a mold.

As shown in FIGS. 1 and 2, the shape of each blade 7 is such that the wall thickness is not uniform and becomes smaller at the base end 8 and tip end 9, and thicker at the middle part 10. There is. For example, in the case where the outer diameter of the impeller is 140 m, the length C in the extending direction is 14.2 mm, the base end 8 and the tip end 9 are blunted, and the maximum blade thickness W, is 2.1 fins.

The blades of the impeller have a dimensional ratio (Wm/
C) is set to 0.148.

The maximum dimension ratio (Lm/C) of 1 in the distance between the line S connecting the inlet end and the outlet end and the pressure surface with respect to the length C of the blade between the inlet end and the outlet end is 0°. It is 23.

The size ratio (U, /C) of the maximum value U in the distance between the line S connecting the inlet end and the outlet end and the suction surface to the length C of the blade between the inlet end and the outlet end is 0. It is preferably 0.5 to 0.3°, and in this example it is 0°37.

The air flow path 13 formed by the pressure surface 11 and the negative pressure surface 12 of mutually adjacent blades has a dimension ratio of the outlet end side to the inlet end side dimension of preferably 0.4 or more and 0.8 or less, and 0.4
If it is smaller than 0.8, the air is likely to be turbulent due to sudden blowout near the outlet, and if it is larger than 0.8, it becomes difficult to obtain sufficient blowout pressure.

In this case, as shown in FIG. 2, the radius R1 of the circle inscribed on the artificial end side of the air flow path 13 is approximately 7°5,
The radius R1 of the circle inscribed on the exit end side is approximately 4.0 fl.
The air flow path 1 is gradually formed to have the dimensions of
3 is narrow, and the outer to inner dimension ratio is about 0.53.

The exit angle (A) is set at approximately 10 degrees in this example,
The entrance angle (B) is set to approximately 85 degrees. This design is due to the fact that the air inflow angle is approximately radial.

Further, the mounting angle (D) is set to approximately 41 degrees.

The shape of the suction surface and pressure surface of the blade 7 is made by combining a plurality of circular arcs and spline curves.

Further, as shown in FIG. 4, the angle θ formed by the tip end that takes in air and the base end that blows out air with respect to the center of the impeller is about 7.5 degrees.

The results of an experiment regarding the air blowing efficiency of a centrifugal blower using an impeller with the above configuration will be explained with reference to FIGS. 5 to 8.

Figure 5 shows the flow direction of air blown outward from the impeller 3, and the flow of air blowing outward from the impeller to the inside of the blowout case is directed to the tangent W of the impeller, as shown by the arrow ■. On the other hand, the direction of air blowing is gentler than that of the conventional blowing direction V', and the angle at which the air blows against the case 2 becomes smaller, so that the impact when the air blows against the case 2 can be reduced. Therefore,
Energy loss can be reduced, efficiency can be improved, and noise caused by blowing can be prevented.

Furthermore, according to this embodiment, separation and turbulence of the air flowing between the adjacent blades 7 is also prevented, which further increases the efficiency of air blowing by the blower and also prevents noise in the blades 7. can.

In Fig. 6, the horizontal axis represents the discharge wind ff1 (Irr/h),
The vertical axis represents the total pressure efficiency ηF (%), and the experimental results of the present invention are plotted in comparison with the conventional results.

Here, the total pressure efficiency η was determined by the following equation.

ηF = (Total pressure GV x wind ff1H of centrifugal blower) ÷ Shaft output of motor (watts) As is clear from Fig. 6, according to this invention, the efficiency of the centrifugal blower is improved by about 10% compared to the conventional one. It is possible to achieve high efficiency even in the lowest discharge air volume range. At the same time, we also measured noise.
The sound was quieter than before.

FIG. 7 shows the case where the ventilation resistance was varied in the measured values shown in FIG. 6, where the solid line represents the present invention and the dashed-dotted line represents the results of an experiment using a conventional impeller. Symbol a in the figure indicates ventilation resistance of 480rrr/h-55mmAq
, b has ventilation resistance of 400d/h -62+n A q
, c has ventilation resistance of 300rr? Ventilation resistance at /h-70mAq, d is ventilation resistance at 600rrr/h-45
The case of mmAq is shown.

As is clear from FIG. 7, in the past, the efficiency differed significantly depending on the ventilation resistance, but in the present invention, even if the ventilation resistance changes, the efficiency is approximately equal, and the efficiency is high from the low air volume range to the high air volume range. can be obtained.

Figure 8 shows the results obtained when the rotational speed was varied in the measured values shown in Figure 6, with the solid line representing the present invention and the dashed-dotted line representing the results of an experiment using a conventional impeller. There is. The symbol e in the figure is when the rotation speed is 150 Orpm.
f indicates the relationship between the discharge air volume and the total pressure efficiency in the case of 3000 rpm. As is clear from FIG. 8, even at low rotation speeds, as shown by symbol e, it is possible to always obtain a higher total pressure efficiency than before, and
Even if the discharge air volume changes, the total pressure efficiency does not change significantly, so you can always expect a stable effect. In addition, as shown by the symbol r, in the case of high rotational speeds, it goes without saying that higher efficiency can be obtained than before, and even when the discharge air volume changes over a wide range, the amount of change in total pressure efficiency is lower than before. It is small compared to , and it is possible to obtain the expected efficiency.

As described above, according to the present invention, high efficiency and low noise can be achieved, and high efficiency can also be achieved in a low air volume region. Furthermore, it was confirmed that there was almost no change in efficiency even when the ventilation resistance was changed. This makes it possible to achieve high efficiency in each mode, even if the device has different ventilation resistance modes, such as a vent and a heater, such as an automobile air conditioner.

Needless to say, the present invention is not limited to automotive air conditioners, but can be applied to other units to achieve similar high efficiency.

(Effects of the Invention) Since the present invention is configured as described above, it produces the following effects.

According to the impeller of the centrifugal blower according to claim 1, the blade has a blade wall shape, and the blade thickness WII with respect to the blade length C.
O ratio (Wffi/C) is 0.14 or more 0°16, distance to pressure surface LffiO ratio (Lffi/C) is 0°2 or more 0
．． 3 or less, and the width of the flow path between adjacent blades is gradually narrowed from the inlet end to the outlet end.
These synergistic effects can reduce noise when air blows against the case and improve efficiency.

According to the impeller of the centrifugal blower according to claim 2, since the outlet angle A is set to 5 degrees or more and 20 degrees or less, the resistance when the blown wind blows against the case is reduced.
Energy loss can be reduced. Therefore, it is possible to further reduce noise and improve efficiency.

According to the impeller of the centrifugal blower according to claim 3, since the inlet angle B is set to 70 degrees or more and 95 degrees or less, air can be taken in smoothly along the blades. By preventing turbulence in the flowing air, it is possible to reduce noise and improve efficiency.

According to the impeller of the centrifugal blower according to the fourth aspect, since the mounting angle is set to 30 degrees or more and 50 degrees or less, separation of air on the negative pressure surface can be prevented.

FIG. 1 is an enlarged side view showing the blades of the impeller according to the present invention, FIG. 2 is a side view showing the air flow path of the impeller, and FIG. 3 is a perspective view showing a part of the impeller. Figure 4 is a side view of an impeller, Figure 5 is a cross-sectional view of a centrifugal blower using an impeller, Figure 6 is a graph showing the relationship between the discharge amount and efficiency of this embodiment in comparison with the conventional one. Figure 7 is a graph showing the relationship between the discharge amount and efficiency when the resistance is changed compared to the conventional one, and Figure 8 is a graph showing the relationship between the discharge amount and efficiency when the rotation speed is changed compared to the conventional one. FIG.

3...impeller, 7...blade, 13...
...Air flow path, proximal end...8.9...
・Tip, A...Outlet angle, B...Inlet angle, C...Installation angle, D...Blade length, G... ...Center line, M...Tangential line to the pressure surface, N...Tangential line to the circumferential surface of the impeller, Ll...
...Distance to the pressure surface, W, ...Maximum thickness, X...Blowout angle.

Figure 3 Figure 4 Figure 5 Figure 6

Claims (4)

[Claims] (1) A plurality of blades extending in the axial direction are arranged on the same circumferential surface, an air flow path is formed between the pressure surface and the negative pressure surface of the adjacent blades, and the centrifugal force causes the impeller to In an impeller of a centrifugal blower that blows air from the inside to the outside, the blades of the impeller have an airfoil shape, and the thickness of the blade with respect to the length (C) of the blade between the inlet end and the outlet end of the air inflow path. The dimension ratio (W_m/C) of the maximum value (W_m) of 0.14 or more is 0
．． 16 or less, the dimension ratio of the maximum value (L_m) of the distance between the line (S) connecting the inlet end and the outlet end and the pressure surface to the length (C) of the impeller between the inlet end and the outlet end ( L_m/C) is 0.2
More than 0.3. An impeller for a centrifugal blower, wherein the width of the air flow path between the adjacent blades gradually decreases from the inlet end to the outlet end. (2) When the angle formed by the tangent (M) of the pressure surface forming the air flow path at the base end of the blade of the impeller and the tangent (N) of the circumferential surface of the impeller is defined as the exit angle (A). The impeller for a centrifugal blower according to claim 1, wherein the outlet angle (A) is 5 degrees or more and 20 degrees or less. (3) At the tip of the blade, when the inlet angle (B) is the angle between the normal (H) to the center line (G) connecting the centers of the impeller and the tangent (J) to the pressure surface at the tip. The impeller for a centrifugal blower according to claim 1, wherein the inlet angle (B) is 70 degrees or more and 95 degrees or less. (4) A line (S) connecting the base end and the tip of the blade
and the center line of the impeller (G) is the installation angle (D).
The impeller for a centrifugal blower according to claim 1, wherein the mounting angle (D) is 30 degrees or more and 50 degrees or less.