JP3111963B2 - Impeller for blower and impeller for blower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade of an impeller for a blower and an impeller for a blower, and more particularly, to a structure in which a longitudinal section in a rotational direction is formed thick at a front edge and thin at a rear edge. The present invention relates to an airfoil-shaped impeller for a blower having one surface as a positive pressure surface and the other surface as a negative pressure surface, and a fan impeller having such a blade.

[0002]

2. Description of the Related Art With respect to the blades of an impeller for a blower, there is widely known a technique of forming a cross section of the blade into an airfoil shape (thick blade shape) in order to improve blowing performance. When the airfoil shape is adopted, the separation of the airflow is suppressed irrespective of the fluctuation of the inflow angle of the air, so that the air blowing performance is improved as compared with the thin blade.

[0003] As a countermeasure for reducing the drawbacks of airfoil-shaped blades, which increase the weight of the blades as compared with thin blade-shaped blades, it is also known that the blades have a hollow structure. Also, such an impeller for a blower
It is often used for outdoor units of air conditioners, and it is desired to reduce noise. The noise generated in the fan impeller is predominantly what is called broadband noise, and is considered to be generated by upstream turbulence, pressure fluctuations on the blade surface, and vortices emitted from the trailing edge of the blade.

A vortex emitted from the trailing edge of the blade, a so-called wake vortex, generates a vortex in such a manner that the airflow flowing along the outer surface of the blade wraps around to the opposite side at the edge of the trailing edge. However, it is considered that they interfere with each other and generate noise. To reduce the generation of noise due to such wake vortices, there have been proposed techniques as shown in Japanese Patent Publication No. 54-31204 and Japanese Patent Application Laid-Open No. 8-189497. In either case, a notch is provided at the trailing edge of the blade to smooth the merger of the airflow flowing along the outer surface of the blade and to reduce the generated noise by reducing the generated vortex. It is composed.

[0005]

In the airfoil-shaped blade described above, since the thickness of the blade is large, if a notch is provided in the trailing edge portion, the blade on the pressure side and the suction side of the blade are provided. An edge is formed in each case, and it is difficult to reduce the vortex generated at the edge of the notch.
Therefore, the vortex generated at the edge of the notch provided at the trailing edge cannot be made sufficiently small, and the effect of suppressing noise generation is diminished.

In consideration of this, it is conceivable to reduce the thickness of the trailing edge of the blade to enhance the effect of noise suppression by the notch, but it is necessary to maintain sufficient strength of the blade at the trailing edge. There is a possibility that the blades may be damaged due to the failure, and there is a concern that noise may be generated due to the thin thickness of the trailing edge portion of the blade. SUMMARY OF THE INVENTION An object of the present invention is to provide a blade of a fan blade for a blower, which reduces a wake vortex at the blade trailing edge portion, suppresses noise generation, and has low noise, and a blade fan blade using the blade. .

[0007]

According to a first aspect of the present invention, a blade of a blower impeller according to the present invention is formed such that a vertical cross section in a rotational direction is formed thick at a front edge portion and thin at a rear edge portion. A blade of an airfoil-shaped blower impeller having a positive pressure surface and the other surface as a negative pressure surface, wherein a plurality of triangular cutouts are provided at a trailing edge, and a serrated portion having a sawtooth shape is provided. Are formed thicker at the center and thinner at the edges.

As a result, the airflow flowing along the outer surface of the blade smoothly merges at the serration portion at the trailing edge, and the generated vortex becomes finer, thereby suppressing noise generation. The thickness at the central portion of the serration portion is formed thicker than at the edge portion, so that sufficient strength can be maintained. The blade of the impeller for a blower according to claim 2 is the blade of the impeller for a blower according to claim 1, wherein the serration portion is one of a positive pressure surface side edge portion and a negative pressure surface side edge portion in the cutout portion. At least one of the edge portions is formed of a smooth curved surface.

In this case, at least one edge of the serration portion is eliminated, and the vortex generated in this portion becomes fine, so that generation of noise can be suppressed. The blade of the impeller for a blower according to claim 3 is the blade of the impeller for a blower according to claim 2, wherein the serration portion is formed by a smooth curved surface at a side of the cutout portion on the negative pressure surface side. ing.

In this case, the generation of the vortex at the edge of the serration portion on the side of the negative pressure surface is reduced, and the vortex generated as a whole becomes finer, thereby suppressing noise. The blade of the impeller for a blower according to claim 4 is the blade of the impeller for a blower according to any one of claims 1 to 3, wherein the serration portion is a rear edge of the blade and is a radially outer periphery. It is provided in a predetermined range from the side.

On the inner peripheral side of the blade, the velocity of the air flow passing through the blade is low, and the turbulence of the wake vortex at the trailing edge of the blade is small. By setting the predetermined range from the side, it is possible to maintain the strength near the base of the blade, which has a large load during rotational driving. A blade of the impeller for a blower according to claim 5 is the blade of the impeller for a blower according to any one of claims 1 to 4, and has a structure having a hollow portion.

As a result, it is possible to reduce the weight of the blade, maintain the strength, and reduce the amount of material used to reduce the cost. The impeller of the blower impeller according to claim 6 is the impeller of the impeller for a blower according to claim 5, wherein the impeller has a recess provided on one surface thereof and a recess formed on the impeller body. And a lid member having an edge portion joined to an edge portion of the recess of the blade main body, and the blade main body and the lid member form a hollow portion.

In this case, by joining the blade main body and the lid member, it becomes easy to configure a blade of a blower impeller having a hollow portion. The impeller for a blower according to claim 7 is a hub mounted on a rotating shaft of a driving source, and a plurality of the impellers mounted on the outer periphery of the hub at equal intervals in a rotational direction. And a blade of the impeller for a blower described in (1).

As described above, the wake vortex generated at the trailing edge of the blade can be made fine, and a low-noise fan impeller can be constructed.

[0015]

1 and 2 show an outdoor unit 10 for an air conditioner employing a propeller fan (impeller for a blower) 1 according to an embodiment of the present invention. As shown in FIG. 1, the outdoor unit 10 includes a heat exchange room 8 and a machine room 9, and both rooms are separated by a partition plate. The motor 4 having the propeller fan 1 mounted on the rotating shaft 4 a is provided in the heat exchange chamber 8.
And a heat exchanger 5 having an L-shaped cross section are provided, and a bar-shaped blowout grill 6 is fitted on the front surface. When the propeller fan 1 is rotated by the motor 4,
Along the direction of the arrow indicated by the two-dot chain line in FIG.
Flows from the blowing grill 6 to the front of the outdoor unit 10 (downward in FIG. 1). In addition, propeller fan 1
Rotates in the direction of the arrow shown in FIG. In the machine room 9,
The compressor unit 7 and electric components (not shown) are arranged.

The propeller fan 1 is, as shown in FIG.
Cylindrical hub 2 mounted on rotating shaft 4a of motor 4
And a plurality of blades 3 joined to the outer peripheral surface of the hub 2 at a predetermined inclination angle in the blowing direction. Hub 2
A groove or the like (not shown) is formed in the inner peripheral portion of the motor shaft 4 so as to be non-rotatably fitted to the rotating shaft 4a of the motor 4. In this embodiment, as shown, a propeller fan 1 having three blades 3, 3 is employed.

The blade 3 has a blade body 31 as shown in FIG.
And a lid member 32 as shown in FIG. The blades 3 have a structure called a so-called forward blade, and have a shape in which the front edge portion is advanced in the rotational direction toward the outer peripheral side in order to improve aerodynamic performance, and the inflowing air current (air). In order to reduce the degree of peeling, particularly the degree of peeling of the leading edge, the leading edge portion has a rounded thick wing shape (airfoil shape). Correspondingly, as shown in FIG. 5, the blade main body 31 has a rounded thick-walled front edge 33, a rear edge 34 corresponding to the blade rear, a front edge 33 and a rear edge. An intermediate thin portion 36 in which a recess 35 is formed on the suction side at a position intermediate the edge 34.
And

At the edge of the recess 35, steps 37, 37 which are joined to the edge of the lid member 32 are formed discontinuously. When the lid member 32 is fitted into the recess 35, the surface of the step portion 37 comes into contact with the inner surface of the lid member 32, and the blade body 31 and the lid member 32 are joined by ultrasonic welding. As shown in FIG. 7, the step portion 37 is connected to the recess 35 by a curved surface 38 and guides a liquid such as a water droplet attached to the recess 35 to a joint between the blade main body 31 and the lid member 32. It is configured as follows. In addition, positioning protrusions 39 for positioning the lid member 32 are provided at appropriate positions of the step portion 37 of the blade main body 31. In the illustrated example, the positioning projections 39 are provided at three positions.

The rear edge 34 of the blade body 31 is provided with a serrated portion 51 having a plurality of triangular cutouts and formed in a sawtooth shape. FIG. 10 shows details of the serration section 51. The serration unit 51
A plurality of cutouts 52 are formed by cutting the rear edge 34 in a triangular shape. Triangular sawtooth-shaped projections 53 project rearward between the cutouts 52. Protrusion 53
Is cut along the rotation direction of the blade body 31, and the thickness decreases from the front to the rear corresponding to the shape of the rotation direction vertical cross section of the blade body 31.
Further, a radial vertical cross section 55 obtained by cutting the projection 53 along the radial direction of the blade main body 31 is formed on the negative pressure surface 5 of the blade main body 31.
The thickness is set so as to decrease from the sixth side toward the positive pressure surface 57 side. Therefore, as shown in the enlarged sectional view of FIG. 12, the projection 53 has a suction surface 56 at the edge thereof.
The edge on the side is shaved to form a smooth curved surface, and only the edge 58 on the pressure side 57 is present.

The blade body 31 is configured so that its thickness decreases from the front toward the apex 59 of the notch 52 so as to smoothly continue with the projection 53 at a portion continuous with the projection 53. Therefore, as shown in FIG. 11 (A), the XIA-XIA cross section of the blade main body 31 is set so that the thickness in the radial vertical cross section is uniform. Also, as shown in FIG. 11B, the XIB
The -XIB cross section is set such that the thickness of the radial vertical cross section is reduced at a position corresponding to the vertex 59 of the notch 52. FIG. 11C shows the XIC-X of FIG.
FIG. 9 shows an IC cross section, in which an outer surface of a projection 53 on a negative pressure surface 56 side is curved toward an edge 58 on a positive pressure surface 57 side,
This shows that the thickness of the radial longitudinal section decreases toward the edge.

When the blade body 31 is used as described above, the airflow flowing along the suction surface 56 side of the blade body 31 and the airflow flowing along the pressure surface 57 side of the blade body 31 are notches 52.
Will gradually merge from the front to the rear. Therefore, the vortex generated at the trailing edge portion 34 of the blade main body 31 becomes a fine vertical vortex, and the generation of a large wake vortex can be prevented. Further, since the edge of the projection 53 has the edge 58 only on the positive pressure surface 57 side, as shown in FIGS.
The airflow flowing along the positive pressure surface 57 goes around the edge 58 and generates a vortex to form a fine vertical vortex, which can prevent generation of a turbulent wake vortex. Thus, generation of noise due to the wake vortex can be eliminated as much as possible.

The lid member 32 has a shape that abuts against the step portion 37 of the blade main body 31 and is fitted into the recess 35.
Of the negative pressure side. The lid member 32 is provided with positioning recesses 40, 40 corresponding to the positioning projections 39, 39 of the blade main body 31. An energy director 48 is formed on the inner surface side of the lid member 32 at a position corresponding to the step portion 37 of the blade main body 31. The energy director 48 is melted by ultrasonic vibration by an ultrasonic horn and welds the step portion 37 of the blade main body 31 and the edge portion of the lid member 32. As shown in FIG. It is configured in a square shape.

The lid member 32 aligns the positioning recess 40 with the positioning projection 39 of the blade main body 31,
In the recess 35. Thereafter, the blade body 31 and the lid member 32 are joined by ultrasonic welding or the like, and the blade 3 having the hollow portion 41 is configured. The blade body 31 and the lid member 32 are joined by melting the energy director 48 provided on the lid member 32 at the position where the step portion 37 is provided. The blade body 31 and the lid member 32
At the position where the step portion 37 does not exist at the joint portion with the above, a slight gap communicating from the hollow portion 41 to the outside is formed.

The cover member 32 is provided with discharge port concave portions 42, 43, and 44 at three locations on the edge portion. The outlet recesses 42, 43, and 44 are provided so that the lid member 32 is
When joined to the hollow portion 41, the hollow portion 41 communicates with the hollow portion 41.
Outlet 4 for discharging liquid such as water droplets that have entered in 1
5, 46 and 47. 14 and 15
As shown in FIG.
1 is provided. The projection 61 is formed integrally with the blade main body 31, and swells toward the negative pressure surface at the outer peripheral portion of the front edge 33. A point P shown in FIGS. 14 and 15 indicates a vertex of the protrusion 61. This projection 61
Is located on the upstream side in the rotation direction of the discharge port 45 located at the outer peripheral side front edge when the propeller fan 1 rotates, and its surface is outside the surface of the discharge port 45. The protrusion 61 has a smooth hill shape, and the rear inclined surface 62 on the side closer to the outlet 45 is the front inclined surface 6 farther from the outlet 45.
It is steeper than No. 3 (see FIG. 15). Further, the protrusion 61 extends not only from the front portion toward the upstream in the rotation direction of the discharge port 45 but also from the surface of the discharge port 45 over the side portion toward the upstream in the rotation direction of the discharge port 45. (See FIG. 14).

When a discharge port for discharging the liquid penetrating into the hollow portion is provided, when the propeller fan is driven to rotate, air flows in from the discharge port to generate a wind noise, which resonates in the hollow portion to generate noise. Could be a source. In particular, in the forward wing as described above, generation of noise at the outlet 45 provided on the front end side becomes a problem. Therefore, the outlet 4
By providing a projection 61 in front of 5, airflow separation at this position is increased, so that air does not flow into the discharge port 45.

Specifically, as shown in FIG. 16, when the propeller fan 1 rotates, the airflow that has come into contact with the front edge 33 of the blade 3 separates at a downstream position past the discharge port 45. 32 will be attached again. Further, on the downstream side of the projection 61, the position and vector of the eddy current generated by the separation change, and the hollow portion 4
1 is suppressed. For this reason, it is possible to suppress the generation of the wind noise and the occurrence of the resonance phenomenon due to the inflow of the air into the outlet 45, and to suppress the generation of the noise.

Here, the projection 61 is attached to the blade main body 31.
Since the protrusions 61 are formed integrally, no process such as joining the protrusions is required, and since the protrusions 61 are formed as hills, the rotation resistance of the propeller fan 1 is reduced and the rotation efficiency is improved. Further, since the inclination of the rear inclined surface 62 is steeper than the inclination of the front inclined surface 63, the amount of air flowing along the rear inclined surface 62 and flowing into the outlet 45 is reduced. Thereby, the phenomenon that air flows into the hollow portion 41 is further suppressed, and the wind noise and the resonance phenomenon are also suppressed.

Further, an L-shaped heat exchanger 5 is provided in the outdoor unit 10 for the air conditioner, and air is sucked from two surfaces of the heat exchanger 5, so that the direction of the air flowing into the blades 3 is changed. Is easy to fluctuate. On the other hand, in the propeller fan according to this embodiment, the protrusion 61 is formed not only on the upstream side in the rotation direction of the discharge port 45 but also on the side toward the upstream side in the rotation direction.
5, the air flow into the discharge port 45 can be suppressed even when the flow direction of the air flowing into the blade 3 changes.

In the propeller fan 1 in which three forward wings are arranged as in this embodiment, when the motor 4 is not driven, the state shown in FIG. 4 is relatively stable. Often stays in a state.
Each of the blades 3 in this state is shown as 3A, 3B,
In the case of 3C, in the blade 3A, the lowermost position of the hollow portion 41 coincides with the position of the discharge port 45. In the blade 3B,
The lowermost position of the hollow portion 41 matches the position of the discharge port 46,
In the blade 3C, the lowermost position of the hollow portion 41 coincides with the position of the discharge port 47. Such outlets 45, 4
6 and 47, the outlet recess 42 of the lid member 32 is positioned at the lowermost end of the hollow portion 41 of each blade 3 at the rotational position where the propeller fan 1 is in a stable state when not driven. , 43, and 44 are set.

The inner surface of the recess 35 of the blade main body 31 and the inner surface of the lid member 32 have the same smooth surface finish as at least the outer surface of the blade main body 31 and the outer surface of the lid member 32. This is because the blade body 31 and the lid member 32
This can be realized by making the mold for making the mirror finish. If necessary, a water repellent can be applied to the recess 35 of the blade body 31 and the inner surface of the lid member 32 by spraying a water repellent.

In the above-described propeller fan 1, the water droplets that have entered the hollow portion 41 of the blade 3 generate
The inner surface of the recess 35 of the blade body 31 and the inner surface of the lid member 32 are guided in the outer peripheral direction by centrifugal force, and are discharged from the discharge ports 45 and 46 and the unwelded gaps on the outer peripheral side. When the propeller fan 1 is not driven, FIG.
A stable state is established at the rotational position shown in FIG. At this time, the water droplets that have penetrated into the hollow portion 41 of the blade 3 are located at the lowest portion of each of the blades 3 and 3 due to the inner surface of the recess 35 of the blade body 31 and the inner surface of the lid member 32 formed on the smooth surface. To the discharge ports 45, 46, 47. The edge of the recess 35 is connected to the step 37 by a curved surface 38, and the recess 3
5 and the water droplets guided on the inner surface of the lid member 32 are:
The blade body 31 and the lid member 32 are guided by the gaps where the welding is not performed and the discharge ports 45, 46, and 47, and are discharged to the outside. [Other Embodiments] The number of blades is not limited to the above-mentioned embodiment, but may be two or four or more.

[0032]

The blades of the impeller for a blower according to the present invention are:
Since the serrations are provided at the trailing edge, the airflow flowing along the pressure side and the airflow flowing along the suction side gradually merge to generate fine vortices, and In order to prevent the generation of a vortex, the generation of noise can be suppressed. In addition, the thickness of the serration portion in the radial vertical section is formed thin at the edge portion, so that even if the serration portion is provided on the airfoil-shaped blade, a large eddy current is not generated at the edge of the serration portion. It has become. Therefore, it is possible to prevent the generation of turbulent wake vortices at the trailing edge of the blade, and to minimize the generation of noise.

Further, since the impeller for a blower according to the present invention uses the blade of the impeller for a blower as described above, a low-noise blower can be constituted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an air conditioner outdoor unit to which an embodiment of the present invention is applied.

FIG. 2 is a front view thereof.

FIG. 3 is a perspective view of a propeller fan according to one embodiment of the present invention.

FIG. 4 is a plan view thereof.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a plan view of a blade main body.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is a plan view of a lid member.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 8;

FIG. 10 is an enlarged perspective view of a main part of a blade main body.

FIG. 11 shows XIA-XIA, XIB-XIB, XIC-XI of FIG.
C sectional drawing.

FIG. 12 is a sectional view taken along line XII-XII of FIG. 10;

FIG. 13 is an explanatory diagram showing a flow of air.

FIG. 14 is a partially enlarged plan view of a blade.

FIG. 15 is a sectional view taken along line XV-XV in FIG. 14;

FIG. 16 is an explanatory diagram showing a flow of air.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 propeller fan 2 hub 3 blade 31 blade body 32 lid member 35 recess 37 step 38 curved surface 41 hollow portion 45 outlet 46 outlet 47 outlet 47 energy director 51 serrated portion 52 cutout portion 53 protrusion 56 negative pressure surface 57 positive Compression face 58 edge

Continued on the front page (72) Inventor Eiichi Kitano 1304 Kanaokacho, Sakai-shi, Osaka Daikin Industries, Ltd. Sakai Works Kanaoka Factory (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 29/30

Claims (7)

(57) [Claims] The thickness of the longitudinal section in the direction of rotation has a leading edge (33).
And a thinner surface at the trailing edge (34), with one surface being a pressure surface (57) and the other surface being a suction surface (56).
An airfoil-shaped impeller for a blower, wherein a plurality of triangular cutouts (52) are provided in the trailing edge (34), and serrations (51) having a sawtooth shape are provided.
Radial longitudinal section (55) of the serration (51)
The blade of the impeller for a blower, the thickness of which is formed thick at the center and thin at the edge. 2. The serration portion (51), wherein at least one of a pressure side edge portion and a suction side edge portion of the notch (52) is formed of a smooth curved surface. A blade of the impeller for a blower according to claim 1. 3. A blade of an impeller for a blower according to claim 2, wherein said serration portion (51) is configured such that a side edge portion of said notch portion (52) on the suction side is formed with a smooth curved surface. 4. The serration section (51) includes a blade (3).
The impeller for a blower according to any one of claims 1 to 3, wherein the rear edge (34) is provided in a predetermined range from a radially outer peripheral side. 5. The impeller blade for a blower according to claim 1, which has a hollow portion (41). 6. A blade body (31) having a recess (35) on one surface, and a recess (35) of said blade body (31).
The edge portion is recessed (3) in the blade body (31).
6. The blower according to claim 5, further comprising: a lid member (32) joined to an edge portion of (5), wherein the blade body (31) and the lid member (32) form the hollow portion (41). 7. Impeller blades. 7. A hub (2) mounted on a rotating shaft (4a) of a drive source (4), and a plurality of hubs mounted on the outer periphery of the hub (2) at equal intervals in a rotational direction. 1-6
And a blade (3) for a fan impeller according to any one of the above.