JP3007766B2 - Mixed flow fan - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixed flow fan used for an exhaust blower and an air conditioner.

[0002]

2. Description of the Related Art In recent years, it is required that exhaust air blowers and air conditioners used in living and non-living spaces reduce noise generated during operation.

Conventionally, this kind of mixed flow fan is generally shown in FIG. Hereinafter, the configuration will be described with reference to the drawings.

As shown in FIG. 1, a plurality of blades 101
Are attached to an annular casing 112 along the outer peripheral edge 103 while maintaining a constant clearance in the circumferential direction. The blade 101 has a shape in which the center of the chord is advanced in the rotation direction from the root portion 104 of the blade 101 toward the outer peripheral edge 103. Further, the casing 112 and the casing 1 are provided downstream of the rotor blade 101.
The stationary blades 108 are arranged between the inner cylinders 113 in the inner tube 12 so as to support the inner cylinder 113.

[0005] In the above configuration, the general ventilation direction when the mixed flow fan rotates is that air is passed through the mixed flow fan.

[0006]

In such a conventional mixed flow fan, when the air flows on the blade surface from the leading edge to the trailing edge, the fluid does not flow completely in accordance with the theory, so that the moving blade There is a case where the flow does not follow the blade 101. In addition, there is a problem that separation is likely to occur on the negative pressure surface of the blade due to deceleration near the surface due to the viscosity of the fluid, and furthermore, there is a problem that rotation noise is generated due to rotation of the moving blade 101. Also, turbulence when the fluid collides with the hub 102 is one of the causes for increasing noise.

[0007] The present invention has been made to solve the above problems, and has as its first object to reduce noise generated during operation.

A second object is to increase the air flow and improve the efficiency.

[0009]

In order to achieve the first object, a mixed flow fan according to the present invention comprises a plurality of moving blades on an outer periphery of a hub. When the inlet outer diameter is D2i and the outlet outer diameter is D2o in the shape,
When D2i / D2o is in the range of 0.85 to 0.9 and the inlet inner diameter is D1i and the outlet inner diameter is D1o, D1i / D
When 1o is in the range of 0.45 to 0.55 and the width of the moving blade in the direction of the rotation center axis is L, L / D
2o is in the range of 0.28 to 0.3, and the average of the mounting angles with the rotation center axis of the inner peripheral edge of the bucket blade is 52 ° to
It is configured to have a range of 55 °.

In order to achieve the first object and the second object, the second means is that the difference in the mounting angle between the inner peripheral edge and the outer peripheral edge in the shape of the moving blade is in the range of 3 ° to 10 °. When the blades are viewed from the direction of the rotation center axis, the pitch angle between the blades at the point where the outer diameter becomes the maximum is θt, and both end points of the outer peripheral edge that make the maximum are formed in the radial cross section with the rotation center axis. When the angle is θs, θs / θt is 0.94.

A third means for achieving the first object is that when the inlet diameter of the hub is D3i and the outlet diameter is D3o, D3i / D3o is in the range of 0.4 to 0.43. , And has a streamlined configuration.

In order to achieve the first object, a fourth means is provided downstream of the moving blade, between the casing and the substantially frustoconical inner cylinder in the casing, When the inlet area and the outlet area in the radial cross section of the stator vane blade that supports
When the speed at the inlet of the stator blade is Vi and the speed at the outlet of the stator blade is Vo,
The fluid velocity ratio Vo / Vi from the inlet of the stationary blade to the outlet of the stationary blade is 0.9 or less.

[0013]

According to the first aspect of the present invention, the fluid flowing on the wing surface can be smoothly guided without abruptly increasing the speed, so that separation on the wing surface can be reduced.

According to the configuration of the second means, by assuming a forced vortex flow on the blade surface, the amount of work at the outer periphery of the blade is increased, the air flow is increased, and the fluid flowing on the blade surface is smoothed. The noise can not be increased by flowing.

[0015] Further, according to the configuration of the third means, air turbulence colliding with the hub can be reduced.

In addition, the configuration of the fourth means makes it possible to stabilize the fluid flowing from the rotor blades in a state parallel to the axis without disturbing the fluid, to eliminate a swirl component, and to reduce the pipeline resistance.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG.

As shown in the figure, a plurality of rotor blades 1 are provided on the outer periphery of a hub 2, the average of the mounting angles is θ, and the outer diameter of the outlet is D2.
o, when the inlet outer diameter is D2i, the outlet inner diameter is D1o, the inlet inner diameter is D1i, and the axial width of the moving blade 1 is L, θ is in the range of 52 ° to 55 °, and D2i / D2o is 0. .8
5 to 0.9, and D1i / D1o is 0.45 to
0.55, and L / D2o is 0.28 to 0.3.
It consists of the range.

With the above configuration, the moving blade 1 can smoothly flow the flow on the blade surface during the rotating operation without abruptly increasing the speed, thereby reducing noise.

Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

As shown in the drawing, the difference between the average values of the mounting angles at the inner peripheral edge 4 and the outer peripheral edge 3 is 3 ° to 10 ° in the configuration of the first embodiment.
Where θt is the pitch angle between the blades and θs is the angle formed between both ends of the outer peripheral edge, and θs / θt is 0.94.

With the above configuration, the work volume of the portion near the outer peripheral edge 3 increases during the rotating operation of the moving blade 1, so that the air volume increases, and the moving surface of the moving blade 1 is less warped. Fluid can flow smoothly. Further, since the fluid on the outer peripheral portion 3 of the positive pressure surface 11 is made to work reliably, no fluid is entrapped on the negative pressure surface 10 in the middle of the moving blade 1.

Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

As shown in the drawing, if the inlet diameter of the hub 2 is D3i and the outlet diameter of the hub 2 is D3o in the structure of the first and second embodiments, D3i / D3o is 0.4 to 0.43.
It is composed in the form.

According to the above configuration, the fluid that collides with the hub 2 during the rotating operation of the bucket blade 1 can be made to flow smoothly.
Further, the fluid flowing on the surface of the hub 2 is not easily separated.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

As shown in the drawing, the stationary blade 8 installed between the casing 12 and the inner cylinder 13 in the casing 12 has the structure of the first, second, and third embodiments.
The exit area at the radial cross section is So, and the entrance area is Si
Where So / Si is in the range of 1.2 to 1.4, and when the speed of the inlet portion is Vi and the speed of the outlet portion is Vo, the fluid speed ratio Vo / Vi from the inlet portion to the outlet portion. Is 0.9 or less.

With the above configuration, the fluid flowing from the moving blade 1 is stabilized without being disturbed in a state parallel to the rotation center axis 9, and a swirl component is generated when the fluid is discharged to the outlet of the stationary blade 8. Elimination can reduce pipeline resistance.

[0029]

As is apparent from the embodiments, as described above, according to the present invention, the fluid flowing on the surface of the moving blade and the surface of the hub and at the outlet of the stationary blade is smoothly increased without abrupt increase in speed. Can be provided, a separation can be reduced, and a mixed flow fan which does not increase noise can be provided.

Further, it is possible to provide a mixed flow fan that increases the amount of work on the outer peripheral portion of the moving blade and increases the air flow.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a mixed flow fan according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the mixed flow fan according to the second embodiment.

FIG. 3 is a front view of the same.

FIG. 4 is a side sectional view of the mixed flow fan according to the third embodiment.

FIG. 5 is a side sectional view of the mixed flow fan according to the fourth embodiment.

FIG. 6 is a side sectional view of a conventional mixed flow fan.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rotor blade 2 hub 3 outer peripheral edge 4 inner peripheral edge 8 stator blade 9 rotating center axis 12 casing 13 inner cylinder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-136597 (JP, A) JP-A-1-118000 (JP, A) Fully open 1979-167807 (JP, U) Fully open 1979 20100 (JP, U) Actually open 1979-101506 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 29/18-29/38 F04D 23/00 F04D 11/00 101

Claims (4)

(57) [Claims] A plurality of rotor blades provided on an outer periphery of a hub;
When the inlet outer diameter is D2i and the outlet outer diameter is D2o in the shape of the bucket blade, D2i / D2o is 0.85 to 0.85.
0.9, the inner diameter of the inlet is D1i, and the inner diameter of the outlet is D1i.
When 1o, D1i / D1o is 0.45 to 0.55
And L / D1o is in the range of 0.28 to 0.3, and L / D1o is in the range of 0.28 to 0.3, and the width of the inner peripheral edge of the blade is A mixed flow fan characterized in that the average of the mounting angle with the rotation center axis is in the range of 52 ° to 55 °. 2. A difference in mounting angle between a rotation center axis at an inner peripheral edge and an outer peripheral edge in a shape of a rotor blade is 3 ° to 10 °.
°, the pitch angle between the moving blades at the point where the outer diameter is maximum when the moving blades are viewed from the direction of the rotation center axis is θt, and both end points of the outer peripheral edge that are the maximum are When the angle between the rotation center axis and the cross section in the radial direction is θs,
2. The method according to claim 1, wherein θs / θt is 0.94.
Mixed flow fan as described. 3. The hub has an inlet diameter of D3i and an outlet diameter of D3o.
The mixed flow fan according to claim 1 or 2, wherein D3i / D3o is in a range of 0.4 to 0.43, and has a streamlined shape. 4. A downstream of the bucket blade, between the casing and a substantially frustoconical inner cylinder within the casing,
When the inlet area of the stator blade supporting the inner cylinder in the radial cross section is Si and the outlet area is So, So / Si is in the range of 1.2 to 1.4. Assuming that the speed of the inlet portion is Vi and the speed of the outlet portion of the stator blade is Vo, the fluid velocity ratio Vo / Vi from the inlet portion of the stator blade to the outlet portion of the stator blade is 0.9 or less. The mixed flow fan according to claim 1, 2 or 3, wherein