JP3060083B2 - Turbo fan and device equipped with turbo fan - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus equipped with a turbofan and a turbofan used for air blowing and ventilation in an air conditioner or the like.

[0002]

2. Description of the Related Art In many cases, a turbo fan for an air conditioner is built in an indoor unit and installed indoors, and it is desirable that noise (blast sound) generated by the blow of the turbo fan be low. Since the blowing noise is generally proportional to the sixth power of the fan rotation speed, the lower the rotation speed is, the lower the blowing noise is for a fan having the same blowing volume. Further, since the blowing sound has a component proportional to the sixth power of the maximum airflow velocity at the fan outlet, lowering the airflow velocity at the fan outlet has an effect of reducing the blowing sound. Conventionally, a turbo fan uses an airfoil in a fan blade (hereinafter referred to as a blade) cross-sectional shape to reduce blowing noise, and a suction inlet diameter is set to a blade inlet diameter to improve performance at a low pressure operating point. In order to increase the airflow and to increase the blowing capacity, a method such as a three-dimensional design of the turbofan itself has been used. For example, Japanese Unexamined Patent Publication (Kokai) No. 2-95797 discloses that, in order to improve the performance at a low pressure operating point, the suction diameter is increased and the suction diameter and the blade inlet diameter are designed at an optimum ratio to the blade outer diameter. It is disclosed that the blade airfoil shape is changed near the blade inlet in order to reduce the blowing noise generated by the turbulence of the air flow at the mouth.

[0003]

When the blade cross section is made to be an airfoil, variation due to uneven shrinkage caused by a change in wall thickness when a synthetic resin is used for the blade, and assembly when press forming a sheet metal. Variations caused by the work are difficult to predict with the current technology, and the variations are absorbed by adjustment after assembly, so that the number of adjustment steps increases. When a three-dimensional shape is used for the blade, molding using a synthetic resin is very expensive because the mold is divided into a plurality of parts, and requires welding for each part. There are factors that make it difficult to reduce costs, such as increasing the manufacturing process.

[0004] It is an object of the present invention to achieve low-cost blower noise reduction for a device equipped with a turbofan and a turbofan.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a substantially disk-shaped boss provided with a hole for mounting a motor drive shaft on a central axis, and a boss on one surface of the boss. A plurality of blades spirally implanted around the hole for mounting the motor drive shaft, a funnel-shaped shroud disposed on the side facing the boss with the blade interposed therebetween, and An impeller constituted by a hub disposed in contact with the outer peripheral edge of the boss; and a motor for rotating the impeller by engaging the drive shaft with the motor drive shaft mounting hole. In the turbo fan, the blade has a blade cross-sectional shape in a cross section obtained by cutting the impeller along a plane perpendicular to the center axis, from the center end of the blade to the position of a radius R with respect to the center axis. As it gets closer to the outer periphery of the vehicle, And so that curve, shake the position of radius R - up to the edge after de are those blade surface has a shape closer to a parallel line of the extended line of a straight line connecting the position of the radius R of the central axis and the blade.

[0006]

According to the above construction, the blade shape in the cross section obtained by cutting the impeller along a plane perpendicular to the center axis forms an inflection point at a position of a predetermined radius R, and the center end of the blade is formed. From the point of inflection to the front of the fan in the direction of rotation of the fan, and from the point of inflection to the trailing edge of the blade, the curve changes to form a concave or vertical curve toward the front in the direction of fan rotation. . As a result, the exit pressure of the airflow can be locally increased because the exit angle of the blade becomes large at the exit of the impeller, and the same air volume can be obtained at a low rotation speed as compared with a case where the blade has no inflection point. Can be. Further, by changing the distance from the position of the inflection point to the outlet of the impeller (blade trailing edge) between the hub and the shroud, the rate of local pressure rise is changed, thereby changing the hub and shroud at the outlet of the impeller. It is possible to reduce the maximum velocity of the outlet airflow while maintaining the same air flow rate by making the velocity distribution of the outlet airflow uniform between the outlets. As described above, since the blowing sound has a portion proportional to the sixth power of the maximum speed of the outlet airflow, the reduction in the maximum speed of the outlet airflow greatly contributes to the reduction of the blowing sound.

Further, since the blade shape is a two-dimensional shape, the integral extraction molding is performed by using a method disclosed in Japanese Patent Application Laid-Open No. 61-197800 (hereinafter, this method is referred to as an integral molding method). It is possible, and it is possible to eliminate variations in performance and strength.

[0008]

FIG. 1 is a partially broken plan view and a longitudinal sectional view of a turbofan 1 according to a first embodiment of the present invention. The turbo fan 1 has a substantially disk-shaped boss 3 provided with a motor drive shaft mounting hole 2 in the center, an annular hub 4 connected to the outer peripheral edge of the boss 3, and one end of the boss 3. A plurality of blades 5 implanted on one surface of the boss 3 and the hub 4 and extending in a direction parallel to the motor drive shaft, and the boss 3 sandwiching the plurality of blades 5 therebetween. And a funnel-shaped shroud 6 arranged opposite to the hub 4 and connected to the other ends of the plurality of blades 5.
And a motor 7 having a motor driving shaft 8 coupled to the motor driving shaft mounting hole 2 of the boss 3. The boss 3 has a conical shape in which the center portion where the motor drive shaft mounting hole 2 is provided projects toward the shroud 6, and the large diameter side of the shroud 6 facing the boss 3 faces the boss 3 side. The smaller diameter side faces away from the boss 3. The central axis of the shroud 6 and the axis of the motor drive shaft mounting hole 2 of the boss 3 are located on the same straight line.

As shown in FIG. 1, the cross section taken along a plane perpendicular to the axis of the motor drive shaft mounting hole 2 of the blade 5 (hereinafter referred to as the axis of the impeller) becomes closer to the center of the impeller. Being forward in the rotation direction, showing a spiral shape almost from the outer periphery of the impeller toward the central axis, a portion near the outer periphery of the impeller is partially bent so as to be perpendicular to the outer periphery of the impeller. I have. A position where the blade shape is bent so as to be perpendicular to the outer peripheral edge of the impeller, that is, a straight line connecting the axis of the impeller and the outer peripheral edge from the rear in the rotational direction (hereinafter referred to as a radius line). The distance (radius R) from the motor drive shaft 8 at the position 9 changing in the direction along
And between shroud 6. The distance of the blade trailing edge 5A from the impeller axis is the minimum at the position where the blade trailing edge 5A contacts the hub 4, and linearly approaches the position where the blade trailing edge 5A contacts the shroud 6 therefrom. It is getting bigger. In other words, a straight line connecting the tangent of the blade surface with the center axis and the position of the radius R of the blade from the center side end of the blade to the position of the radius R around the axis (center axis) of the blade impeller. The tangent at a position where the angle is closer to the radius R is larger, and the angle is smaller as the tangent is closer to the blade trailing edge from the radius R to the trailing edge of the blade. Therefore, as shown in the figure, the blade forms a convex curve forward in the impeller rotation direction from the center end of the blade to the position of the radius R, and the blade is the impeller from the position of the radius R to the trailing edge of the blade. It has a concave curve forward in the rotation direction.

In the example shown in FIG.
Has a maximum radius of 210 mm. The maximum radius of the hub 4 is 195m
m. , Radius R9 is 200 mm. It is.

FIG. 2 shows a blade sectional shape when the impeller is cut in several planes perpendicular to the motor drive shaft 8. The cross-sectional shape of the blade in FIG.
A, section BB and section CC. Section A-
A, in section B-B, the blade trailing edge 2
The position where the distance from 0 to 21 changes from the axis of the impeller to the direction where the blade shape changes along the radius line (position of radius R) 2
The blade is parallel to the radius line near the trailing edge of the blade because it is larger than the distance to 3, 24. In section CC, the distance from the axis of the impeller to the trailing edge 22 of the blade. Is smaller than the distance from the axis of the impeller to the position (position of radius R) 25 where the blade shape changes in the direction along the radius line, and the outer peripheral end of the blade remains in the shape facing backward in the rotational direction. is there.

In sections AA and BB, at positions 23 and 24, the blade surface changes so as to approach the direction along the radius line with the same curvature. As represented by the cross-sections AA and BB, the lengths of the portions 23-20 and 24-21 in which the blade surface changes along the radius line become longer from the hub 4 to the shroud 6. ing.

The shape of the blade, which is changed so as to approach the direction along the radius line, has a function of increasing the pressure of the air flow near the impeller outlet where the air flow exits the impeller. For this reason, a predetermined air volume can be obtained at a low rotation speed, and the blowing noise is accordingly reduced. The part whose shape has changed so as to approach the direction along the radius line (the part parallel to the radius line)
If the length of is increased from the hub toward the shroud, the effect of increasing the pressure increases as the distance from the hub to the shroud increases. By this action, the pressure distribution at the outlet of the impeller can be improved, and the velocity distribution of the air flow between the hub and the shroud at the outlet of the impeller can be made uniform. When the velocity distribution of the airflow is made uniform, the maximum velocity is reduced for the same ventilation volume, and the maximum velocity of the ventilation sound is 6 times.
The portion proportional to the power is reduced, and the blowing noise as a whole is reduced.

FIG. 3 shows a conventional turbo fan in which the shape is not changed so as to approach the direction along the radius line near the blade rear end, and the other parts are the same as the conventional fan and the blade rear end is near the blade rear end. 2 is a graph showing a comparison of characteristics of the turbofan shown in FIG. 1 in which the shape is changed so as to approach a direction along a radius line. This graph takes the air volume on the horizontal axis,
The outlet pressure and the specific noise are plotted on the vertical axis, and the data of the embodiment of the present invention are indicated by black circles and the data of the prior art are indicated by white circles. The illustrated data is the same as the data of the embodiment of the present invention and the data of the conventional art at the same rotation speed, and the air volume is changed by providing an obstacle (damper) at the fan outlet. From the figure,
When the same air volume is generated, it can be seen that the embodiment of the present invention has low noise and high outlet pressure.
The fact that the outlet pressure can be increased indicates that the resistance (blowing resistance) on the outlet side of the blower can be changed with a margin.

Further, in the case of this shape, the blade is formed on a plane parallel to the axis of the impeller, and a turbofan can be formed by an integral molding method using the above synthetic resin. Mass production using a synthetic resin is possible, and a turbofan having no variation in product performance and strength can be produced at low cost.

FIG. 4 shows two examples in which the blade shape is changed along the radius line in the blade section when cut along a plane perpendicular to the axis of the impeller. Blade section 40
Is a blade shape changed at a position 41 with a curvature, and a blade cross section 42 is a blade shape changed at a position 43 in a polygonal line. When a blade is made of synthetic resin, it must be sharply
The blade section 32 whose direction is changed is not preferable because of the whitening phenomenon of the resin, the durability of the mold, and the problem of mass productivity.

FIG. 5 is a partially crushed plan view and a longitudinal sectional view of a second embodiment of the present invention. The turbo fan 51 has a substantially disc-shaped boss 53 provided with a motor drive shaft mounting hole 52.
And an annular hub 54 coupled to the outer peripheral edge of the boss 53
A plurality of blades 55, one end of which is implanted on one surface of the boss 53 and the hub 54 and extends in a direction parallel to the motor drive shaft 58; An impeller comprising a funnel-shaped shroud 56 disposed opposite to the boss 53 and the hub 54 and having the other ends of the blades 55 coupled thereto; and a motor drive shaft of the boss 53. A motor in which a motor drive shaft 58 is connected to the mounting hole 52
Data 57. The present embodiment and the first
The difference from this embodiment is that the hub 54 of this embodiment is wider than the hub 4 of the first embodiment, and the blade rear end portion 55A is a straight line substantially parallel to the impeller axis. , In the plane AA perpendicular to the motor drive shaft 58.
In the cross section of the blade, the distance from the motor drive shaft at the position 59 where the blade shape changes from the rearward direction along the radius line is constant from the hub to the shroud, and the other components are This is the same as the first embodiment.

That is, unlike the first embodiment, the distance of the trailing edge of the blade of the impeller from the axis of the impeller is substantially constant from the hub to the shroud. The cross-sectional shape of the blade in a plane perpendicular to the impeller axis is AA, B shown in the figure.
-B and CC are almost the same in each cross section. Therefore, at the position 59 in the cross section AA, the cross section BB, and the cross section CC, the blade surface changes so as to be parallel to the radius line with the same curvature, and the portion where the blade surface is parallel to the radius line. Are approximately the same length.

The shape of the blade, which is changed to be parallel to the radius line, has the function of increasing the pressure of the airflow near the blade outlet. For this reason, a predetermined air volume can be obtained at a low rotation speed. However, it is difficult in the present embodiment to change the pressure rise between the hub and the shroud as in the first embodiment. The conversion is not obtained as much as in the first embodiment.

However, in the case of this shape, the molding is performed by integral molding.
Since a bofan can be produced, mass production using a synthetic resin is possible, and a turbofan without variation in product performance and strength can be produced at low cost.

FIG. 6 is a partially broken plan view and a longitudinal sectional view of a third embodiment of the present invention. This embodiment differs from the second embodiment in that the position 69 at which the blade 65 changes so as to be parallel to the radial line approaches the impeller axis as the distance from the hub 64 to the shroud 66 increases. The other components are the same as in the second embodiment. That is, in the blade cross section on a plane AA orthogonal to the impeller axis, the distance from the impeller axis at the position 69 where the blade shape changes from backward to be parallel to the radius line is from the hub to the shroud. It becomes smaller toward.

When the impeller 61 is cut along a plane perpendicular to the axis of the impeller shown in FIG. 6, a cross section AA, a cross section BB,
FIG. 7 shows a blade cross-sectional shape along the cross-section C-C. Section A
In the sections A, B-B, and C-C, the distance from the impeller axis to the blade trailing edges 73, 74, 75 is larger than the positions 76, 77, 78 from the impeller axis, respectively.
The blade shape changes in any direction so that the blade surface approaches parallel to the radius line. Also, section A
-A, cross section BB, cross section CC
The length of the portion where the sliding surface changes in a direction approaching parallel to the radius line increases as the distance from the hub to the shroud increases.

The shape of the blade whose blade surface has changed (curved) in a direction approaching parallel to the radius line has the function of increasing the pressure of the airflow near the blade outlet. For this reason, a predetermined air volume can be obtained at a low rotation speed. Also, by increasing the length of the portion of the blade that has changed (bent) approaching parallel to the radius line from the hub to the shroud, the effect of increasing the pressure increases from the hub to the shroud. By this operation, the velocity distribution of the airflow between the hub and the shroud can be made uniform at the impeller outlet. In the present shape, the distribution of the pressure rise can be provided more than in the second embodiment, but since the blade shape becomes three-dimensional, it is difficult to use the integral molding method.

FIGS. 8, 9 and 10 show examples in which the uniformity of the flow velocity distribution is further promoted by devising the impeller outlet shape with respect to the first embodiment. FIG. 8 shows the blade trailing edge 85A formed by two arcs, and FIG. 9 shows the blade trailing edge 95A.
FIG. 10 shows the blade trailing edge 105.
A is formed by a polygonal line. Hub 84,
It is intended to rapidly realize a change in the amount of pressure increase at the impeller outlet between the shrouds 94, 104 and the shrouds 86, 96, 106. However, it is difficult to use an integral molding method for these shapes due to restrictions such as a mold.

When the blade and the hub are shaped as shown in FIG.
As described above, there is a possibility that a state in which the impeller touches the ground may occur.
In such a state, if the blade is made of synthetic resin,
In some cases, defects such as chipping of 11 or bending of sheet metal may occur. In such a case, by providing the temporary hub extension 124A as shown in FIG. 12, even when the impeller outlet is set to be in contact with the ground, the impeller exit end face 121 is missing.
It is possible to prevent a defect such as bending.

FIG. 13 shows an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an indoor unit for an air conditioner equipped with the turbofan shown in FIG. The illustrated indoor unit has a box-shaped outer box 132 with one side open, a motor 131 internally fixed to the bottom surface of the outer box 132, and a motor fixed to the motor 131 and rotated to rotate the outer box. 132, an impeller 130 for sucking air from the open surface of the outer case 132 and discharging the air in a direction parallel to the bottom surface;
32, a heat exchanger 136 disposed opposite the discharge port of the impeller 130, and a suction cone 134 disposed so as to cover the periphery of the intake port of the impeller 130.
A grill filter 135 that is arranged to face the air inlet of the impeller 130 and covers the open surface of the outer box 132 to form an air inlet, and covers the peripheral edge of the open surface of the outer box 132. A panel 133 disposed to form an air outlet between the grill filter 135 and an outer peripheral edge thereof;
An electrical component 137 such as a temperature sensor that is disposed near the impeller 130 in the outer box 132 and detects the air temperature is configured.

In the indoor unit having the above-described structure, the air passes through the grill filter 135 from the room and passes through the suction cone 134.
While being rectified by the impeller 130,
Is cooled or heated by the heat exchanger 136 and then sent out from the air outlet into the room. According to the present embodiment, the fan rotation speed can be made lower than in the case of the conventional blade to obtain the required air volume, and the blowing noise can be reduced accordingly.

FIG. 14 shows an example of a ventilator equipped with a turbofan according to the present invention. In the present embodiment, a turbo fan 140 is installed in an opening 144 formed in a wall 143, and a suction grill 141 is mounted on the indoor side of the opening 144, and an exhaust grill 142 is mounted on the outdoor side. The air is drawn into the turbo fan 140 from the room through the suction grill 141, and is discharged outside the room through the exhaust grill 142.

FIG. 15 shows an example of a cooling water cooling device for a vehicle equipped with a turbofan according to the present invention. In this embodiment, a radiator for cooling engine cooling water is arranged in front of an engine room of an automobile, an impeller 150 of a turbo fan arranged behind the radiator, and an impeller 150
And a motor that is arranged at the rear of the rotor and drives the impeller 150 to rotate. This embodiment also has the effect of reducing the blowing noise generated from the cooling water cooling device.

FIG. 16 is a graph showing characteristics of a propeller fan conventionally used for cooling and ventilation in FIG. 3 and comparing with characteristics of a turbo fan. The hatched area indicates the characteristics of the propeller fan, the black circles indicate the characteristics of the turbofan according to the present invention, and the white circles indicate the characteristics of the conventional turbofan. In the propeller fan, the outlet pressure obtained for the same air volume is lower than that of the turbo fan, so that when the pressure coefficient is large (when the blowing resistance is large), the specific noise is large. In addition, when ventilating a room with a high airtightness, which has recently increased, a turbo fan that can generate a higher pressure than a propeller fan is suitable, and noise is low.

[0031]

The turbofan of the present invention comprises a boss, a hub,
The blade cross-section on a plane perpendicular to the axis of rotation of the turbofan (motor drive axis), including a blade and a shroud, has a predetermined radius R from the rotation axis between the hub and the shroud.
Up to the blade trailing edge, the blade surface becomes rearward in the fan rotation direction as it approaches the blade trailing edge, and from the position of a predetermined radius R to the blade trailing edge, the blade surface becomes parallel to the radial line as it approaches the blade trailing edge. This shape has a function of increasing the air flow pressure near the blade outlet, and a predetermined air volume can be obtained at a low rotation speed. Further, by increasing the length of the portion changed to a shape parallel to the radius line from the hub toward the shroud, the effect of increasing the pressure increases in the portion near the shroud. By this action, the velocity distribution between the hub and the shroud at the impeller outlet can be made uniform, and the maximum velocity of the air flow can be reduced. By lowering the number of revolutions of the fan and lowering the maximum airflow velocity at the outlet, an effect of lowering the blowing sound while maintaining a predetermined airflow can be obtained.

Further, according to the present invention, since the integral molding method can be applied to the blade, a mass-produced product having no variation in performance and strength can be produced.

[Brief description of the drawings]

FIG. 1 is a partially broken plan view and a longitudinal sectional view of a turbofan according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view taken along line AA, BB of the embodiment of FIG. 1;
It is a top view which shows the blade cross section in a line and CC line.

FIG. 3 is a graph showing a comparison between the characteristics of the embodiment shown in FIG. 1 and a turbofan of the prior art.

FIG. 4 is a plan sectional view showing another example of the blade shape of the embodiment shown in FIG. 1;

FIG. 5 is a partially broken plan view and a longitudinal sectional view of a turbofan according to a second embodiment of the present invention.

FIG. 6 is a partially broken plan view and a longitudinal sectional view of a turbofan according to a third embodiment of the present invention.

FIG. 7 is a vertical sectional view taken along line AA, BB of the embodiment of FIG. 6;
It is a top view which shows the blade cross section in a line and CC line.

FIG. 8 is a longitudinal sectional view showing an example of the shape of the trailing edge of the blade of the turbofan according to the present invention.

FIG. 9 is a longitudinal sectional view showing another example of the shape of the trailing edge of the blade of the turbofan according to the present invention.

FIG. 10 is a longitudinal sectional view showing still another example of the shape of the trailing edge of the blade of the turbofan according to the present invention.

FIG. 11 is a longitudinal sectional view of the turbofan impeller showing a state where the blade rear end is in contact with the ground.

FIG. 12 is a longitudinal sectional view of a turbo fan according to an embodiment of the present invention.

FIG. 13 is a sectional view of an indoor unit for an air conditioner according to an embodiment of the present invention.

FIG. 14 is a sectional view of a ventilation device according to an embodiment of the present invention.

FIG. 15 is a longitudinal sectional view of an automotive engine cooling water cooling device according to an embodiment of the present invention.

FIG. 16 is a graph showing a comparison between characteristics of a turbo fan according to an embodiment of the present invention, a turbo fan according to the related art, and a propeller fan.

[Explanation of symbols]

1 Turbo fan 2 Motor drive shaft mounting hole 3 Boss 4 Hub 5 Blade 5A Blade trailing edge 6 Shroud 7 Motor 8 Motor drive shaft 9 Blade direction change position 20, 21, 22 -Do trailing edge 23, 24,
Blade direction change position 40 42 Blade 41, 43 Blade direction change position 51 Impeller 52 Motor drive shaft mounting hole 53 Boss 54 Hub 55 Blade 55A Blade trailing edge 56 Shroud 57 Motor 58 Motor drive shaft 59 Position where blade shape changes 61 Impeller 62 Motor drive shaft mounting hole 63 Boss 64 Hub 65 Blade 65A Blade trailing edge 66 Shroud 67 Motor 68 Motor drive shaft 69 Position where blade shape changes 70, 71, 72 blades 73, 74, 7
5 Blade trailing edge 76, 77, 78 Position where blade shape changes 84 Hub 85A Blade trailing edge 86 Shroud 94 Hub 95A Blade trailing edge 96 Shroud 104 Hub 105A Blade trailing edge 106 Shroud 121 Impeller outlet end face 123 Boss 124A Hub extension 130 Impeller 131 Motor 132 Outer Case 133 Panel 134 Suction Cone 135 Grill Filter 136 Heat Exchanger 137 Electricity 140 Impeller 141 Intake-side Grill 142 Exhaust-side Grill 143 Wall 144 Opening 150 Impeller 151 Radiator 152 Motor

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Shimode 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (72) Inventor Makoto Nagai 390, Muramatsu, Shimizu-shi, Shizuoka Prefecture Shimizu, Ltd. Inside the plant (72) Inventor Ryoji Sato 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Inside the Shimizu Plant, Hitachi, Ltd. (72) Inventor Joji Okamoto 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Inside the Shimizu Plant, Hitachi, Ltd. (72) Inventor Shunji Sasaki 390 Muramatsu, Shimizu, Shizuoka Prefecture Inside Shimizu Plant, Hitachi, Ltd. (72) Inventor Masamichi Hanada 390 Muramatsu, Shimizu, Shizuoka Prefecture Inside Shimizu Plant, Hitachi, Ltd. (72) Inventor Hiroki Terada Hiroshiki Terada, Muramatsu, Shizuoka Prefecture 390 Hitachi, Ltd. Shimizu Plant (72) Inventor Shinya Okabe God, Chiyoda-ku, Tokyo Surugadai Yonchome 6 address Hitachi, Ltd. air-conditioning systems business unit (72) inventor Hiroyasu Yoneyama Shimizu, Shizuoka Prefecture City Muramatsu 390 address Hitachi, Ltd. Shimizu in the factory (58) investigated the field (Int.Cl. ^7, DB name) F04D 29/30 F04D 29/28

Claims (10)

(57) [Claims] 1. A substantially disk-shaped boss provided with a hole for mounting a motor drive shaft on a center axis, and a spiral shape on one surface of the boss centering on the hole for mounting the motor drive shaft. And a funnel-shaped shroud disposed on the side facing the boss with the blade interposed therebetween, and a hub disposed in contact with the outer peripheral edge of the boss. A turbo fan comprising an impeller and a motor for rotating the impeller by engaging the drive shaft with a hole for mounting the motor drive shaft, wherein the impeller is perpendicular to the center axis. A curve in which the blade cross-sectional shape of the cross section cut along the surface to be cut is such that the distance from the center side end of the blade to the position of radius R with respect to the center axis is closer to the outer periphery of the impeller in the rotational direction of the impeller. From the radius R to the trailing edge of the blade. In the turbo fan, the blade surface has a shape approaching a parallel line extending from a straight line connecting the center axis and the position of the radius R of the blade. 2. A substantially disk-shaped boss provided with a hole for mounting a motor drive shaft on a center axis, and a spiral shape on one surface of the boss centered on the hole for mounting the motor drive shaft. And a funnel-shaped shroud disposed on the side facing the boss with the blade interposed therebetween, and a hub disposed in contact with the outer peripheral edge of the boss. A turbo fan comprising an impeller and a motor for rotating the impeller by engaging the drive shaft with a hole for mounting the motor drive shaft, wherein the impeller is perpendicular to the center axis. The cross-sectional shape of the blade in the section cut by the surface to be cut is the tangent to the blade surface, the center axis, and the position of the radius R of the blade from the center end of the blade to the position of the radius R around the center axis. The angle between the connecting straight lines is close to the position of the radius R. A tangent line at a position closer to the blade, the larger the angle between the radius R and the trailing edge of the blade, the smaller the angle of the tangent at a position closer to the trailing edge of the blade. 3. The turbofan according to claim 1, wherein a trailing edge of the blade of the impeller connects a trailing edge of the blade to a contact point of the shroud and a trailing edge of the blade to a contact point of the hub. A target characterized by having irregularities with respect to a straight line.
Bofan. 4. The turbo fan according to claim 3, wherein
An annular hub extension is provided at the outer peripheral end of the hub, and the radial size of the hub extension is adjusted by a blade trailing edge inside a cylindrical portion formed by connecting the outer peripheral end of the shroud and the outer peripheral end of the hub extension. A turbo fan having a size to accommodate a convex portion. 5. The turbofan according to claim 1, wherein a distance from a position of a radius R of the blade to a trailing edge of the blade decreases from the shroud side to the hub side. Turbo fan. 6. The turbofan according to claim 1, wherein the size of the radius R decreases from the hub to the shroud. 7. The tar according to claim 1, wherein
A turbofan, wherein the blade material is mainly a synthetic resin material. 8. A blower for sucking and discharging indoor air,
An air conditioner indoor unit comprising: a heat exchanger disposed on a suction side or a discharge side of the blower to heat or cool air passing through the blower, wherein the blower is any one of claims 1 to 7. An indoor unit for an air conditioner, which is the turbofan according to any of the first to third aspects. 9. An air-cooled heat exchanger for circulating a heat medium,
A cooling device comprising: a blower for blowing cooling air to the heat exchanger, wherein the blower is the turbofan according to any one of claims 1 to 7. 10. A blower including a prime mover and an impeller rotationally driven by the prime mover, a suction side grill arranged on an air suction side of the impeller, and an air discharge side of the impeller. A ventilator including an exhaust grill to be arranged, wherein the blower is the turbofan according to any one of claims 1 to 7.