JPH01315695A - Impeller in multi-blade blower - Google Patents

Abstract

PURPOSE:To aim at enhancing the air-blow capacity characteristic with a cheap arrangement by providing a large diameter cylindrical column having a thickness greater than that of the tip of a blade on the inner peripheral side of an impeller, at the tip of the blade, extending in the longitudinal direction of the blade. CONSTITUTION:A blower is composed of a cross fan or an impeller 1, a stabilizer 2, a rear guider 3, several partition plates 4 arranged at predetermined intervals, and several blades 5 each disposed between each adjacent partition plates 4. In this arrangement, a cylindrical column 6 is provided at the tip end of each blade 5, extending in the longitudinal direction of the blade 5. Further, the diameter T of the cylindrical column 6 is set to be larger than the thickness (t) of the tip end of the blade 5. With this arrangement, the flow loss by impingement is reduced when air flows into the blades 5, thereby it is possible to enhanced the flow rate characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to multi-blade impellers such as crossflow fans and sirocco fans that are widely used as blowers for air conditioners and the like.

As an example of a conventional multi-blade blower, a -stage cross-flow blower is disclosed in Japanese Patent Application Laid-Open No. 17296-1982 and Japanese Utility Model Application No. 167990-1983.
The configuration was as shown in the publication.

In other words, as shown by the arrow in Fig. 9, the cross-flow blower is
Due to its structure, it has features not found in other blowers, such as the inflow and outflow directions of the air being opposite to each other, or the fact that when the blower is extended in the axial direction, the air volume increases almost in proportion to its length. has become widely used in recent years.

In addition, as shown in FIG. 9(b), the pitch angle between the blades 8 of the impeller is arranged randomly without periodicity, and the audible rotation sound of 1 sound (nz sound, n: rotation speed, 2 ：Number of blades) is also known.

A general NZ sound frequency analysis characteristic is shown in FIG. 4(,), and a NZ sound frequency analysis characteristic based on a random number arrangement of the pitch between blades is shown in FIG. 5(b).

Another example is the configuration of a centrifugal blower as shown in Japanese Utility Model Publication No. 60-12959.

The centrifugal blower shown in FIG. 10 has a structure in which fluid flows in radially or obliquely at the impeller inlet, spreads radially at the outlet C, and flows out. This structure is often used in places with high static pressure and heavy loads, and the impeller d
It has also been attempted to improve aerodynamic characteristics and airflow characteristics by changing the shape of the airfoil into an airfoil shape.

Problem to be Solved by the Invention Regarding the former cross-flow blower, as described above, when the pitch angles of the blades are arranged irregularly, turbulence occurs in the air flowing between the blades, resulting in a decrease in air volume.

Regarding the latter centrifugal blower, the blades are shaped like airfoils,
Although efforts are being made to improve efficiency, since the blade is thick, there is a risk that it will be heavier, and even if it has a hollow structure, the number of man-hours will increase and the cost will increase.

The present invention solves the above problems and provides a low-cost multi-blade blower with improved air volume characteristics.

Means for Solving the Problems In order to solve the above problems, the multi-blade blower of the present invention is provided with a cylindrical part extending in the longitudinal direction at the tip of the blade on the inner peripheral side of the impeller and having a diameter larger than the diameter of the blade tip. It is something that

Effect: With the above-described configuration, the collision loss of the flow when air flows into the blades is reduced, and the air volume characteristics can also be improved.

Examples Some examples of the present invention will now be described with reference to the accompanying drawings.

First, a case in which the present invention is employed in a cross flow fan will be described with reference to FIGS. 1 to 3. Here, since the basic structure of the blower employing the cross-flow fan is the same as that shown in FIG. 9, the basic structure will be explained using FIG. 9.

In the figure, 1 is a cross flow fan (hereinafter referred to as an impeller), 2 is a stabilizer, 3 is a rear guider, 4 is a partition plate arranged at a predetermined interval, and 5 is a blade arranged between the partition plates 4. It is.

These constitute a well-known blower.

In FIG. 1, a cylindrical portion 6 extending in the longitudinal direction of the blade 5 is provided at the tip portion on the inner peripheral side of the blade 5. As shown in FIG. The diameter T of this cylindrical portion 6 is set larger than the thickness t of the tip of the blade 5, as shown in FIG.

In the blower having the above configuration, when the arrangement pitch of each blade 5 is set at random numbers (unequal intervals), as shown in FIG.
, ), and if the arrangement pitch of each blade 5 is set at equal intervals, the result will be as shown in FIG. 2(b).

Next, the flow of air across the blades 5 in the multi-blade blower configured as described above will be explained using FIG. 3.

Conventionally, wind noise similar to edge tones (aerodynamic noise) was generated when the blades crossed the air flow in response to the suction flow, and air volume characteristics were significantly impaired due to collision loss when the air flowed in.

Therefore, by providing the cylindrical portion 6 on the inner circumferential side of the blade 5, peeling is less likely to occur even if there is a slight discrepancy between the direction of the suction flow and the blade angle.

Therefore, the reduction in air blowing efficiency and the generation of noise due to exposure are reduced.

FIG. 5 is a graph comparing the air volume characteristics of the conventional structure and the present invention in a cross-flow blower.

In the figure, e is a conventional fan whose blades have a random pitch angle, d is a fan whose blades have an equal pitch, and f
1 is a fan of the present invention, in which the pitch angle of the blades is random, and the blade is provided with a cylindrical portion 6.7.

As can be seen from the figure, the air volume of random fans tends to decrease as the rotation speed increases, compared to uniform pitch fans.

However, with the configuration of the present invention, by providing the cylindrical portions 6 and 7 on the inner circumferential side of the random fan, it was possible to obtain air volume characteristics comparable to a uniform pitch, and the air blowing performance was improved.

The contents and results of experiments with this configuration are shown below.

Fan specifications Fan diameter: 86mrn Number of blades = 36 Inside/outside diameter ratio: Approx. 0.79 Blade tip wall thickness: Approx. 0, 5rn Diameter of cylinder part 6: Approx. 1rnrn Diameter of cylinder part 7: Approx. 1mm Number of stations = 8 As described above, by providing the cylindrical part 6 having a diameter larger than the thickness of the tip of the blade 5 at the tip of the blade on the inner peripheral side of the impeller and extending in the longitudinal direction of the blade 5, the air volume characteristics can be improved. It is measured. Furthermore, the airfoil-like shape of the blade can be molded to be lightweight and at relatively low cost.

Furthermore, the present invention can be similarly implemented with a centrifugal blower as shown in FIG.

In other words, such an impeller, as shown by the arrow in the same figure,
It has a characteristic that air flows in from an axial direction or an oblique direction, expands in a radial direction, and flows out, and has a configuration in which a cylindrical portion is provided at the tip of the impeller on the inner diameter side of the blade 5.

Even in this configuration, good results similar to those shown in FIG. 5(C) can be obtained.

In the figure, 1 is an impeller, 2a is a spiral casing, 3a is a boss portion, 4 is a partition plate, 5 is a blade, and 6 is a columnar portion.

In each of the above embodiments, the cross-flow fan has been described in the case of a so-called multi-unit configuration in which the partition plates 4 are arranged at predetermined intervals in the axial direction, but the same operation and effect can be obtained in the case of a single unit. Needless to say, you can obtain

Effects of the Invention As is clear from the above embodiments, the present invention provides an impeller for a multi-blade blower that extends over the entire length of the blade at the tip of the blade on the inner peripheral side of the impeller, and It also has a cylindrical part with a large diameter, which can improve the air volume characteristics.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the blade portion of a cross-flow impeller according to an embodiment of the present invention, FIGS. 2(a) and (b) are sectional views of different cross-flow blowers each equipped with the same blade, and FIG.
The figure is an explanatory diagram illustrating the state of air flow by the same blade, and Figures 4 (,) and (b) are perspective views of a centrifugal impeller and a blower equipped with the same impeller, respectively, showing other embodiments of the present invention. FIG. 5 is a characteristic diagram showing a comparison of the air volume and rotation speed of a conventional blower with a different configuration and a blower according to the present invention, and FIGS. 6(a) and (b) are cross-sectional perspective views of a cross-flow blower, respectively. FIG. 7 is a partially cutaway perspective view of a different conventional impeller. 1... Impeller, 2... Stabilizer,
3... Rear guider, 4... Partition plate, 5
...Blade, 6...Cylindrical part. Fig. 1 (Q) (b) 3・-Pos section 4- Partition plate Fig. 4 (QJ 1, /J) Fig. 5 Rotating fall → Fig. 6 (a no 78°

Claims (1)

[Claims] In an impeller in which a plurality of blades are arranged on the periphery of the end plate or partition plate between circular end plates or partition plates arranged at predetermined intervals, and between the end plates or partition plates,
A multi-blade blower in which a cylindrical part extending over the entire length of the blade is provided at the tip of the blade on the inner circumferential side of the impeller, and the diameter of this cylindrical part is larger than the wall thickness of the part of the blade where it connects to the cylindrical part. impeller.