JP2000110783A - Centrifugal fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a fan efficiency and reduce power consumption of a centrifugal fan used for a ventilating fan. SOLUTION: A shroud suction opening diameter Ds of a turbo fan 1, letting the external diameter thereof is D, is not less than 0.5D, and a blade minimum diameter Di1 is smaller than the shroud suction opening diameter Ds and not more than 0.6D. An end 5a on the suction side of an inducer 5 positioned closer t the center than the blade suction opening diameter Di2 inclines toward direction of rotation. The end 5a on the suction side of the inducer and a plane M vertical to a rotation axis 6 makes an angle of inclination of 90 degrees at the blade suction diameter Di2. Air flow 7 coming from the shroud suction opening 3a is able to be guided up to a blade suction opening 4a while air turbulence is controlled. Thus, the efficiency of the fan is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a centrifugal blower used for a ventilation blower.

[0002]

2. Description of the Related Art A conventional centrifugal blower will be described with reference to FIG.

[0003] A shroud suction diameter Ds of 0.5 D or more with a fan outer diameter D in which a plurality of blades 104 are attached so as to be sandwiched between a main plate 102 and a shroud 103,
In the centrifugal blower having the turbo fan 101 whose blade minimum diameter Di1 is smaller than the shroud suction diameter Ds, the conventional blade minimum diameter Di1 is 0.6D or more.

[0004]

In such a conventional centrifugal blower, the airflow flowing from the shroud suction port is suddenly turned in the centrifugal direction while reaching the blade suction port, and the inner diameter is larger than the blade suction diameter Di2 of the blade. In the inducer section on the side, the collision of the air stream on the pressure side of the inducer section and the separation of the air stream on the negative pressure side of the inducer section cause a problem that the air stream is disturbed and the efficiency is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and suppresses sudden turning of an airflow, and also suppresses airflow collision at an inducer portion positive pressure surface and airflow separation at an inducer portion negative pressure surface. It is another object of the present invention to provide a centrifugal blower capable of improving fan efficiency and reducing power consumption.

[0006]

In order to achieve the above object, the centrifugal blower of the present invention has a fan outer diameter D in which a plurality of blades are mounted so as to be sandwiched between a main plate and a shroud, and has a shroud suction diameter Ds of 0.1 mm. 5D or more, the blade minimum diameter Di1 is smaller than the shroud suction diameter Ds, and the blade minimum diameter Di1 is 0.6D or less. A turbocharger in which the suction end of the inducer portion is inclined in the rotation direction, and the inclination angle α formed by the plane perpendicular to the rotation axis and the suction end of the inducer portion is 90 ° in the blade suction diameter Di2. It was a fan.

Another means is a turbo fan in which an inclination angle α formed by a plane perpendicular to the rotation axis and an end portion on a suction side of an inducer portion gradually decreases toward an inner peripheral side.

Another means is a turbo fan having a thick portion on the negative pressure surface of the inducer portion.

Another means is that the total number of blades is
This is a turbo fan having a small number of blades having an inducer portion.

Another means is a turbofan in which adjacent inducer portions have different shapes.

According to the present invention, there is provided a centrifugal blower capable of improving the efficiency of a fan and reducing power consumption.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a fan outer diameter D having a plurality of blades mounted so as to be sandwiched between a main plate and a shroud, and a shroud suction diameter Ds of 0.5 D or more;
The blade minimum diameter Di1 is the shroud suction diameter Ds.
Smaller and the blade minimum diameter Di1 is 0.6D
In the following turbo fan, the inducer suction side end of the inducer part on the inner peripheral side of the blade suction diameter Di2 of the blade is inclined in the rotation direction, and rotates with the inducer suction side end. A centrifugal blower having the turbo fan having an inclination angle α formed by a plane perpendicular to the axis and having the blade suction diameter Di2 of 90 ° is provided. It is possible to guide the turbulence to the suction port while suppressing the turbulence, and by inclining the suction side end of the inducer section in the rotation direction, it is possible to reduce the collision of airflow on the inducer section positive pressure surface and the airflow on the inducer section negative pressure surface. The angle of inclination α formed by the plane perpendicular to the rotation axis and the suction-side end of the inducer portion is determined by the blade suction diameter D. By setting i2 to 90 °, it is possible to prevent the airflow flowing along the shroud from the shroud suction port from colliding with the inclined portion of the inducer portion at the blade suction port and disturbing the airflow. Has the effect of increasing the air flow-static pressure characteristics and improving the fan efficiency.

[0013] Further, the centrifugal blower having the turbofan has an inclination angle α formed by a plane perpendicular to the rotation axis and the suction-side end of the inducer portion, and the inclination angle α gradually decreases toward the inner peripheral side. On the side, the axial velocity component of the airflow flowing from the shroud suction port can be smoothly converted into the circumferential velocity component and the radial velocity component, and the turbulence of the airflow on the inner peripheral side can be suppressed and guided to the blade suction port, This has the effect of increasing the air flow-static pressure characteristics during the same rotation and improving the fan efficiency.

Further, the present invention is a centrifugal blower having the turbo fan provided with a thick portion on a vacuum surface of the inducer portion, and suppresses separation of airflow behind the inclined portion of the inducer portion on the vacuum surface of the inducer portion. This has the effect of increasing the air flow-static pressure characteristics during the same rotation and improving the fan efficiency.

In addition, the centrifugal blower having the turbo fan has a smaller number of blades having an inducer portion with respect to the total number of blades, and ensures a sufficient flow area even when the number of blades is increased. In addition, the airflow can be guided to the blade suction port while suppressing turbulence, and the airflow-static pressure characteristics at the same rotation can be increased, and the fan efficiency can be improved.

Further, the centrifugal blower having the turbo fan having the different shape of the adjacent inducer portion is provided, and the shape of the adjacent inducer portion is different, so that the flow path area is secured and the rotation direction is improved. By optimizing the shape of the rear inducer for changes in the direction of airflow due to adhesion and separation at the front inducer in the rotation direction, airflow collision loss can be reduced, and Has the effect of increasing the air flow-static pressure characteristics and improving the fan efficiency.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0018]

(Embodiment 1) As shown in FIG. 1 or FIG.
Plural blades 4 sandwiched between main plate 2 and shroud 3
A turbo fan 1 having a shroud suction diameter Ds of 0.5 D or more at a fan outer diameter D having a blade attached thereto, a blade minimum diameter Di1 smaller than the shroud suction diameter Ds, and a blade minimum diameter Di1 of 0.6 D or less. The inducer portion suction side end 5a of the inducer portion 5 on the inner peripheral side with respect to the blade suction diameter Di2 of the blade 4 is inclined in the rotation direction 8, and the inducer portion suction side end 5a and the rotating shaft 6 Angle of inclination α formed by vertical plane M
Has a turbo fan 1 having a blade suction diameter Di2 of 90 °.

With the above configuration, when the turbo fan 1 rotates to obtain a static pressure and a flow rate, the provision of the inducer section 5 suppresses the turbulence of the air flow 7 flowing from the shroud suction port 3a to the blade suction port 4a. And the inducer section suction side end 5
By inclining a in the rotation direction 8, it is possible to suppress the collision of the airflow 9 on the inducer unit pressure surface 5b and the separation of the airflow 9 on the inducer unit negative pressure surface 5c, and also to the inducer unit suction side end. The inclination angle α formed by the portion 5a and the plane M perpendicular to the rotation axis 6 is 90 at the blade suction aperture Di2.
By setting ゜, it is possible to prevent the airflow 7 flowing along the shroud 3 from the shroud suction port 3a from colliding with the inclined portion 5d of the inducer at the blade suction port 4a and disturbing the airflow 7. The air volume-static pressure characteristic during rotation increases, and the fan efficiency can be improved.

(Embodiment 2) As shown in FIG. 1, FIG. 3 or FIG.
The inclination angle α formed by the plane M perpendicular to the inner surface is gradually reduced toward the inner peripheral side.

With the above configuration, when the turbo fan 1 rotates to obtain a static pressure and air volume, the airflow 10 flows through the shroud suction port 3a, and the axial velocity component 10a of the airflow 10 is changed by the inclined portion 5d of the inducer. It is converted to a directional velocity component 10c, and subsequently to a radial velocity component 10b along the inducer section 5 by centrifugal force. At this time, in the airflow 10 flowing from the shroud suction port 3a, the ratio of the axial flow velocity component 10a is larger toward the inner peripheral side, but the inclination angle α gradually decreases toward the inner peripheral side, so that the axial direction of the airflow 10 becomes more toward the inner peripheral side. The conversion of the speed component 10a into the circumferential speed component 10c is promoted, and the force 11 that pushes the airflow 10 toward the outer periphery acts on the inclined portion 5d of the inducer, so that the conversion into the radial speed component 10b is performed smoothly. And the turbulence of the air flow 10 is suppressed, and the blade suction port 4
a, the air flow-static pressure characteristics at the same rotation are increased, and the fan efficiency can be improved.

(Embodiment 3) As shown in FIG. 1 or FIG. 5, the turbo fan 1 has a structure in which a thick portion 12 is provided on an inducer section negative pressure surface 5c.

With the above configuration, when the turbo fan 1 rotates to obtain a static pressure and an air volume, the separation of the airflow 13 behind the inducer section inclined portion 5d of the inducer section negative pressure surface 5c can be suppressed. The air flow-static pressure characteristics at the same rotation are increased, and the fan efficiency can be improved.

The fan efficiency can be further improved by forming the thick portion 12 having the turbo fan 1 in contact with the inclined portion 5 d of the inducer portion and the main plate 2.

Embodiment 4 As shown in FIG. 1 or FIG. 6, a turbo fan 1 having a smaller number of blades 4 having an inducer section 5 than the total number of blades is provided.

With the above configuration, when the turbo fan 1 rotates to obtain a static pressure and an air flow, a sufficient flow area is secured even when the number of blades is increased, and the air flow 14 is not disturbed to the blade suction port 4a. The air flow can be guided while being suppressed, and the air flow-static pressure characteristics at the same rotation can be increased, and the fan efficiency can be improved.

The fan efficiency can be further improved by arranging N and M as arbitrary integers and alternately arranging N blades having an inducer portion and M blades having no inducer portion.

(Embodiment 5) As shown in FIG. 1 or FIG. 7, the turbo fan 1 has a configuration in which adjacent inducer portions 5 have different shapes.

With the above configuration, when the turbo fan 1 rotates to obtain a static pressure and an air flow, the axial height of the rear inducer section 15 in the rotation direction 8 is adjusted by the front inducer section 16 in the rotation direction 8. By optimizing for changes in the direction of the airflow 17 due to adhesion or separation, the flow path area can be secured, the collision loss of the airflow 17 can be reduced, and the air flow-static pressure characteristics during the same rotation increase. Fan efficiency can be improved.

The rear inducer 1 in the rotation direction 8
5, the inclination angle α, the blade minimum diameter Di1, the shape of the thick portion, and the cross-sectional shape of the inducer portion 5 cut along a plane M perpendicular to the rotating shaft 6 at an arbitrary axial height are rotated. By optimizing for changes in the direction of the airflow 17 due to adhesion and separation at the front inducer section 16 in the direction 8,
An equivalent effect can be obtained.

[0031]

As is apparent from the above embodiments, according to the present invention, the air flow flowing from the shroud suction port can be guided to the blade suction port with the turbulence suppressed, and the separation at the inducer portion can be achieved. Thus, it is possible to provide a centrifugal blower capable of suppressing collision, improving the efficiency of the fan, and reducing power consumption.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a centrifugal blower according to embodiments 1, 2, 3, 4, and 5 of the present invention.

FIG. 2 is a circumferential sectional view showing an inducer portion of the centrifugal blower according to the first embodiment.

FIG. 3 is a side sectional view showing a centrifugal blower according to the second embodiment.

FIG. 4 is a side sectional view showing an inducer portion of the centrifugal blower.

FIG. 5 is a side sectional view showing an inducer portion of the centrifugal blower according to the third embodiment.

FIG. 6 is a plan view showing a centrifugal blower according to the fourth embodiment.

FIG. 7 is a plan view showing an inducer portion of the centrifugal blower according to the fifth embodiment.

FIG. 8 is a side sectional view showing a conventional centrifugal blower.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbo fan 2 Main plate 3 Shroud 3a Shroud suction port 4 Blade 4a Blade suction port 5 Inducer part 5a Inducer part suction side end part 5b Inducer part positive pressure surface 5c Inducer part negative pressure surface 5d Inducer inclined part 6 Rotating shaft 7 Airflow D Fan outer diameter Ds Shroud suction diameter Di1 Blade minimum diameter Di2 Blade suction opening 8 Rotation direction 9 Airflow M Plane α Inclination angle 10 Airflow 10a Axial velocity component 10b Radial velocity component 10c Circumferential velocity component 11 Force 12 Thickness Unit 13 Airflow 14 Airflow 15 Rear inducer 16 Front inducer 17 Airflow

Claims (5)

[Claims] 1. A fan outer diameter D in which a plurality of blades are attached so as to be sandwiched between a main plate and a shroud, a shroud suction diameter Ds is 0.5D or more, and a blade minimum diameter Di1 is smaller than the shroud suction diameter Ds. And, in the turbo fan having the blade minimum diameter Di1 of 0.6D or less, the inducer portion suction side end of the inducer portion on the inner peripheral side of the blade suction diameter Di2 of the blade is inclined in the rotation direction, And a centrifugal blower having a turbo fan having an inclination angle α formed by a plane perpendicular to the rotation axis and the suction side end of the inducer portion and having a blade suction diameter Di2 of 90 °. 2. The centrifugal blower according to claim 1, wherein the turbo fan has an inclination angle α formed by a plane perpendicular to the rotation axis and the suction-side end of the inducer portion, and the inclination angle α gradually decreases toward an inner peripheral side. 3. The centrifugal blower according to claim 1, further comprising the turbo fan having a thick portion provided on a vacuum surface of an inducer portion. 4. The centrifugal blower according to claim 1, wherein the turbo fan has a smaller number of blades having an inducer portion than the total number of blades. 5. The centrifugal blower according to claim 1, wherein said turbo fan has different shapes of adjacent inducer portions.