JPS6030500A - Propeller fan - Google Patents

Abstract

PURPOSE:To obtain a large amount of wind and reduce noise and improve the strength of a vane by applying step-press-molding onto the front side of the installation part of a vane seat in the direction of revolution of the vane and forming the rear side of the vane seat into a smooth curved-surface free from step-press-molded part. CONSTITUTION:A vane 10 is step-press-molded only on the front side of the installation part of a vane seat 2 with respect to the direction of revolution of the vane, and a step 10a is formed. Said step-press-molded part 10a has a rounded part at the bent part to prevent stress concentration. The rear side of the vane seat 2 is formed to a smooth vane curved-surface free from step-press-molded part. Therefore, the flow of fluid is made smooth, and the vane having low noise and a little wind-amount loss can be obtained. Since the section modulus of the whole vane is increased by the step-press-molded part 10a, the sufficient strength can be secured by use of a thin plate, and the residual stress can be reduced by the roundness of the curve R of the step-press-molded part, and reliability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a propeller fan, and particularly to a propeller fan that requires a large air volume and has a structure suitable for a high-strength fan.

[Background of the invention]

First, the prior art will be explained with reference to FIGS. 1 to 4.

Figure 1 is a front view of a conventional propeller fan, Figure 2 is a sectional view taken along the line A-A of the blade in Figure 1, and Figure 3 is a conceptual diagram of the blade's deformation during rotation. Figure 4 is.

FIG. 3 is a cross-sectional view of a step-formed portion of a conventional blade.

In the figure, reference numeral 1 denotes a plurality of wings, each of which is made of a thin plate and has a smoothly curved cross section, and is shaped like a flower petal. 2 attaches multiple R1 and drives the drive device (not shown).
In this case, it has a cross-shaped shape with four wings attached to it. 3 indicates a rivet that joins the wing 1 to the product 2. By rotating in the direction of the arrow, the propeller with such a configuration draws in the surrounding fluid and generates a flow of wind above the plane of the paper. This rotation applies mechanical load and pressure to the blade 1.

As a result, stress is generated, conceptually deforming as shown in FIG. FIG. 2 shows a cross section of the wing 1 at rest. Normally, the thickness of R1, the number of rivets 3, the dimensions of Kosan 2, etc. are set to satisfy mechanical strength, but when the thickness and dimensions of the material are increased, the average stress on the blade attachment part due to centrifugal force increases proportionally. There is a limit as it increases. For this reason, steps such as the stepped ribs 1a shown in FIG. 4 are sometimes provided to improve the strength of the blade.

However, it is clear that such stepped ribs impede the flow of fluid, and there is a problem in that losses due to increased resistance reduce the efficiency of the fan and cause the generation of chirping noises.

[Purpose of the invention]

In view of the problems of the prior art, the present invention achieves large air volume and low noise with approximately the same diameter as a conventional propeller fan, and provides a highly reliable solution for improving blade strength. That is its purpose.

[Summary of the invention]

The structure of the propeller fan according to the present invention includes a plurality of blades each having a curved surface made of thin plates, and a component for attaching and fixing the blades to a drive device.
The blade is provided with a stepped molded part only on the front side of the Kosan attachment part with respect to the rotating direction of the tool.

It should be noted that the present invention has developed a triangular shaped fan based on a new theory since it is difficult to achieve high efficiency, low noise, and large air volume with petal shaped fans of the prior art. In order to improve performance, especially air volume and pressure characteristics, with the same diameter as conventional blades, the work of the blades increases. As a result, it is clear that the mechanical strength of the blade is insufficient, and in order to solve this problem, a stepped molding is performed on the front side of the Kosan attachment part in the direction of rotation of the blade, and a stepped molding is performed on the rear side of the Kosan. It has a smooth epidemiological surface with no curves, and the section modulus of the wing has been increased.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIGS. 5 and 6.

FIG. 5 is a front view of a propeller fan according to an embodiment of the present invention, and FIG. 6 is a sectional view taken along the line B-B of the blade in FIG. In FIGS. 5 and 6, parts with the same reference numerals as those in FIGS. 1 to 3 are equivalent to those in the prior art.

In the figure, the number 10 indicates a wing, which is made of a thin plate and has a nearly triangular shape with more straight parts than a conventional petal shape. In the tool 10, steps like IO& are formed by step pressing only on the front side of the butt seat 2 attachment part with respect to the rotational direction of the blade (see arrow). This stepped molded part +Oa has a rounded bent part to avoid concentration of stress. The rear side of Kosan 2 has a smooth curved wing surface with no stepped molding. A propeller fan is constructed by joining a plurality of blades 10 as described above to a conventional fan 2 with rivets 3.

According to the propeller fan having such a configuration, there are no unevenness like the conventional stepped rib structure, and fluid flow becomes smooth. In addition, since the section modulus of the entire blade is increased by the stepped stamped portion 10a, sufficient strength can be ensured with a thin plate. As for the effect of force on the material, the bending radius of the stepped part is rounded and the residual stress is small, making it more reliable than conventional stepped ribs.

Therefore, it is possible to obtain a blade with low noise and low loss of air volume with less disturbance in the flow of lice, and a pod with sufficient strength. In addition, parts other than the blades can be the same as conventional ones, making it economical.

〔Effect of the invention〕

As explained above, according to the present invention, a large air volume and low noise can be achieved with a diameter that is almost the same as that of a conventional propeller fan, and in particular, it provides a highly reliable solution for improving blade strength. It has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a front view of a conventional propeller fan, FIG. 2 is a sectional view taken along the line A-A of the blade in FIG. 5 is a front view of a propeller fan according to an embodiment of the present invention. FIG. FIG. 2...Kosan 10...Wing +Oa...Step pressing molding part. :44 Ison Hikiba #M Shi5m Daisudan 10s

Claims (1)

[Claims] 1. In a propeller fan consisting of a plurality of blades each formed with a curved surface made of thin plates and a screwdriver to which the blades are attached and fixed to the drive device, the blades have a front side of the screwdriver attachment part with respect to the rotational direction of the blades. A propeller fan characterized by having a stepped molded part only in the