JP2537975B2 - Centrifugal blower impeller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller for generating a relatively small amount of air in a centrifugal blower for generating a suction pressure used in a vacuum type electric vacuum cleaner or the like.

2. Description of the Related Art Conventionally, as shown in FIG. 12, an impeller of this type conventionally includes a front shroud 1 and a rear shroud 2 made of sheet metal, and a blade 3 located between the shrouds 1 and 2. Are integrated by being caulked by a caulking portion 4 located on a concentric circle.

In the above structure, the impeller 5 rotates at a high speed to generate the air flow and the suction pressure.

However, in the suction port of the impeller 5 having such a configuration, the air flow is impeller 5 due to the large number of blades 3.
It became difficult to flow into the inside, which was one of the causes of reduced efficiency. As a countermeasure against such a decrease in efficiency, a long blade 6 as shown in FIG. 13 is used.
An impeller 8 having two types of blade lengths, ie, a short blade 7 and a short blade 7, has been proposed. In such an impeller 8, the inflowing airflow rectified by the long blade 6 inside the impeller 8 collides with the suction port side tip edge 9 of the short blade 7 to generate an abnormal sound, and the noise is large as a whole. I had a problem.

When a large amount of small air volume is used, the air flow inside the impeller 8 is rectified, but it is solidified and flows on the rear shroud 10 side of the blades 6 and 7, and the front shroud 11 side becomes a lean flow, and the blades 6, 7 The effect of compressing the air flow tends to be less effective, which is one of the factors that hinder the improvement of the ventilation efficiency.

The present invention is to solve such a problem, by changing the length of the blade in the impeller and devising the suction edge side tip edge shape of the short blade, the blower efficiency is high and the impeller of a low-noise centrifugal blower It is intended to provide.

Means for Solving the Problem And, in order to achieve the above objects, the impeller of the centrifugal blower of the present invention, the length of the blade is composed of two or more types of short and long, such as the following suction port side leading edge of the short blade It is a shape.

That is, the front shroud side half has a shape substantially perpendicular to the flow direction of the air flow, the rear shroud side half is also inclined in the air flow direction, and the suction port side front edge is on the front shroud side with respect to the rear surface shroud side. The shape is located upstream of the air flow.

Action In the above configuration, since the blades in the impeller have different lengths, the number of blades in the suction port of the impeller can be reduced, and the airflow can easily flow into the impeller. Inside, the airflow that has been rectified in a small air volume and solidified on the rear shroud side does not simultaneously collide with the short blade tip edge but collides with it with a time shift and its energy is relaxed, and the airflow is thin. On the side of the front shroud, which has a substantially vertical blade shape, it exerts a force of compressing even a thin air flow, so that these can be combined to improve the blowing efficiency and reduce the noise. Also,
Since the suction port side leading edge of the rear shroud side is inclined so that the front shroud side is located upstream of the air flow with respect to the rear shroud side, the compressive force becomes smaller as it approaches the rear shroud side, and the rear shroud side decreases. When pushing out an air flow whose air flow density increases toward the side, the air flow density from the front shroud side to the rear shroud side can be made uniform. Therefore, a pressure gradient between the rear shroud and the front shroud is less likely to occur, and it is possible to prevent the flow of air flowing from the suction port side to the downstream from being disturbed by the pressure gradient, and to reduce the ventilation efficiency due to the disturbed flow. Can also be prevented.

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 5, 12 is a motor, 13 is its rotating shaft, and 14
Is an impeller fixed to the rotating shaft 13. 15 is impeller
An air guide located on the outer circumference of 14 has an enlarged passage whose passage area is gradually enlarged and a return passage continuing from the enlarged passage. 16
Is a casing that covers the impeller 14 and the air guide 15, and is press-fitted and fixed to the motor bracket 17. Reference numeral 18 is a suction port, 19 is a bearing on the impeller side, and 20 is a bearing holding portion on the side opposite to the bearing 19.

1 to 4 show a first embodiment, in which the impeller 12 is a front shroud 21 and a rear shroud 22 made of sheet metal, and a plurality of caulking portions 2 are integrally arranged between them. A plurality of blades 24, which are different in length, the blades 24 have different lengths, and are composed of a long blade 24a and a short blade 24b and the shape of the tip edge of the short blade 24b on the suction port 25 side, the rear shroud 22. The side half inclines in the flow direction of the air flow and recedes linearly, and the front half shroud 21 side half has a linear shape substantially perpendicular to the flow direction of the air flow, and the suction port side leading edge is on the rear shroud side. On the other hand, the front shroud side is located downstream of the air flow.

By using the impeller 14 having the above-mentioned configuration, compared to the conventional one, it is possible to reduce the degree of congestion of the blades 24 of the suction port 25 in the impeller 15, and the airflow can be smoothly introduced by this rectifying effect. , Impeller
In the inside of 14, the airflow that is rectified and flows on the rear shroud 22 side collides with the tip edge of the short blade 24b while causing a time lag, and in the lean airflow area on the front shroud 21 side, a substantially vertical shape is formed. Since the airflow is efficiently compressed, it is possible to obtain an impeller of extremely high quality, which has high ventilation efficiency and low noise.

Next, FIGS. 6 and 7 show a second embodiment, in which the impeller is
The shape of the tip edge on the suction port 25 side of the 14 short blades 26 is such that the half on the rear shroud 22 side is inclined and retracts in the flow direction of the air flow, and the half on the front shroud 21 side is substantially perpendicular to the flow direction of the air flow. The front end shroud side is located downstream of the rear shroud side with respect to the rear side shroud side.

The configurations shown in FIGS. 6 and 7 have the same effects as those of FIGS. 1 to 4, and the effects are flexible with respect to the flow rate change due to the configuration of the curves. Can be said. However, in the first and second embodiments described above, the shape of the rear shroud side half at the leading edge on the suction port side of the short blade is inclined so that the front shroud side is located downstream of the air flow with respect to the rear shroud side. Therefore, the compressive force increases toward the rear shroud side. Further, since the airflow that is solidified on the rear shroud side has a higher airflow density as it approaches the rear shroud, the airflow with a higher airflow density is pushed out with a larger compression force, and as a result, the airflow on the front shroud side that is pushed out is increased. There is a difference in airflow density between the airflow on the rear side and the airflow on the rear side. Therefore, a turbulent flow is generated in the air flow, which lowers the blowing efficiency. An example in which this point is improved is shown below.

FIG. 8 and FIG. 9 show the third embodiment, in which the shape of the tip edge of the short blade 27 of the impeller 14 on the suction port 25 side is such that the front shroud side half is substantially perpendicular to the air flow direction. Similarly, the rear shroud side half is inclined rectilinearly in the air flow direction and recedes linearly, and the suction port side front edge is located on the front shroud side with respect to the rear shroud side and upstream of the air flow. It is in the shape of.

In this embodiment, since the suction port side tip edge of the rear shroud side half of the short blade 27 is inclined so that the front shroud side is located upstream of the air flow with respect to the rear shroud side, as it approaches the rear shroud side. When pushing out an air flow in which the compressive force becomes smaller and the air flow density becomes larger toward the rear shroud side, the air flow density from the front shroud side to the rear shroud side can be made uniform. Therefore, a pressure gradient between the rear shroud and the front shroud is less likely to occur, and it is possible to prevent the flow of air flowing from the suction port side to the downstream from being disturbed by the pressure gradient, and to reduce the ventilation efficiency due to the disturbed flow. Can also be prevented.

Next, in the fourth embodiment shown in FIGS. 10 and 11, the shape of the tip edge of the short blade 28 of the impeller 14 on the suction port 25 side is set so that the front shroud side half is substantially perpendicular to the air flow direction. Similarly, the rear half of the rear shroud is inclined in the direction of the air flow and recedes linearly, and the leading edge of the suction port is located on the upstream side of the front shroud with respect to the rear shroud. It is in the shape of.

Effects of the Invention As described above, in the impeller of the centrifugal blower of the present invention, the length of the blade is composed of two or more types of short and long, the suction side tip edge of the short blade, half is a substantially vertical shape, Since half of the shape is such that the rear shroud side is retracted with respect to the front shroud side, it is possible to reduce the occurrence of collision noise at the suction side tip edge of the short blade inside the impeller, and The airflow density of the airflow passing through can also be made uniform, and a decrease in the blowing efficiency can be prevented.

[Brief description of drawings]

1 is a side sectional view of an impeller of a centrifugal blower showing a first embodiment of the present invention, FIG. 2 is a side view of a long blade of the impeller, FIG. 3 is a side view of a short blade of the impeller, and FIG. Four
The figure is a plan view showing the same impeller in a cutaway manner, FIG. 5 is a side view showing a partially cutaway view of an electric blower equipped with the impeller of the present invention, and FIG. 6 is a second embodiment of the present invention. Fig. 7 is a side sectional view of the impeller, Fig. 7 is a side view of the short blade of the impeller, Fig. 8 is a side sectional view of the impeller of the third embodiment of the present invention, and Fig. 9 is a side view of the short blade of the impeller. A side view, FIG. 10 is a side sectional view of an impeller of a fourth embodiment of the present invention, FIG. 11 is a side view of a short blade in the impeller, and FIGS. 12 and 13 show a conventional impeller, respectively. It is a sectional side view. 14 …… impeller, 21 …… front shroud, 22 …… rear shroud, 24b, 26,27,28 …… short blade.

Claims (1)

(57) [Claims] 1. A front shroud and a rear shroud,
Composed of a plurality of blades arranged between them, the blade is composed of two or more types of long and short, the suction side tip of the short blade is the downstream side of the air flow from the suction side tip of the long blade. The front shroud side half at the suction port side tip edge of the short blade has a shape substantially vertical to the flow direction of the air flow, and the rear shroud side half is inclined in the air flow direction, and the suction port side An impeller of a centrifugal blower whose front edge has a shape in which the front shroud side is located upstream of the air flow with respect to the rear shroud side.